Python: Azure OpenAI setting fix: Don't fetch AD token if API is present in environment variable. (#8985)

### Motivation and Context

While working on #8951 I found that interacting with an Azure OpenAI
instance I had an API key for, but my identity didn't have IAM access to
the API for, that I was getting a permission error:

```
semantic_kernel.exceptions.service_exceptions.ServiceResponseException: ("<class 'semantic_kernel.connectors.ai.open_ai.services.azure_text_embedding.AzureTextEmbedding'> service failed to generate embeddings", AuthenticationError("Error code: 401 - {'error': {'code': 'PermissionDenied', 'message': 'Principal does not have access to API/Operation.'}}"))
```

I found that this was because, though my API key was set in the
environment, the codepath only recognized an explicitly passed in API
key when deciding whether to issue an AD token while initializing an
AzureTextEmbedding instance.

This PR fixes that by looking at the setting object explicitly, which
may pull the API key from the environment.


### Contribution Checklist

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

Author: lossyrob

python/semantic_kernel/connectors/ai/open_ai/services/azure_text_completion.py

@@ -72,13 +72,21 @@ def __init__(
 
         # If the api_key is none, and the ad_token is none, and the ad_token_provider is none,
         # then we will attempt to get the ad_token using the default endpoint specified in the Azure OpenAI settings.
-        if api_key is None and ad_token_provider is None and azure_openai_settings.token_endpoint and ad_token is None:
+        if (
+            azure_openai_settings.api_key is None
+            and ad_token_provider is None
+            and azure_openai_settings.token_endpoint
+            and ad_token is None
+            and async_client is None
+        ):
             ad_token = azure_openai_settings.get_azure_openai_auth_token(
                 token_endpoint=azure_openai_settings.token_endpoint
             )
 
-        if not azure_openai_settings.api_key and not ad_token and not ad_token_provider:
-            raise ServiceInitializationError("Please provide either api_key, ad_token or ad_token_provider")
+        if not azure_openai_settings.api_key and not ad_token and not ad_token_provider and not async_client:
+            raise ServiceInitializationError(
+                "Please provide either api_key, ad_token, ad_token_provider, or a custom client."
+            )
 
         super().__init__(
             deployment_name=azure_openai_settings.text_deployment_name,

python/semantic_kernel/connectors/ai/open_ai/services/azure_text_embedding.py

@@ -74,11 +74,22 @@ def __init__(
 
         # If the api_key is none, and the ad_token is none, and the ad_token_provider is none,
         # then we will attempt to get the ad_token using the default endpoint specified in the Azure OpenAI settings.
-        if api_key is None and ad_token_provider is None and azure_openai_settings.token_endpoint and ad_token is None:
+        if (
+            azure_openai_settings.api_key is None
+            and ad_token_provider is None
+            and azure_openai_settings.token_endpoint
+            and ad_token is None
+            and async_client is None
+        ):
             ad_token = azure_openai_settings.get_azure_openai_auth_token(
                 token_endpoint=azure_openai_settings.token_endpoint
             )
 
+        if not azure_openai_settings.api_key and not ad_token and not ad_token_provider and not async_client:
+            raise ServiceInitializationError(
+                "Please provide either api_key, ad_token, ad_token_provider, or a custom client"
+            )
+
         super().__init__(
             deployment_name=azure_openai_settings.embedding_deployment_name,
             endpoint=azure_openai_settings.endpoint,

python/tests/unit/connectors/open_ai/services/test_azure_text_completion.py

@@ -11,6 +11,7 @@
     OpenAITextPromptExecutionSettings,
 )
 from semantic_kernel.connectors.ai.open_ai.services.azure_text_completion import AzureTextCompletion
+from semantic_kernel.connectors.ai.open_ai.settings.azure_open_ai_settings import AzureOpenAISettings
 from semantic_kernel.connectors.ai.text_completion_client_base import TextCompletionClientBase
 from semantic_kernel.contents.text_content import TextContent
 from semantic_kernel.exceptions import ServiceInitializationError
@@ -54,6 +55,20 @@ def test_init_with_custom_header(azure_openai_unit_test_env) -> None:
         assert azure_text_completion.client.default_headers[key] == value
 
 
+def test_azure_text_embedding_generates_no_token_with_api_key_in_env(azure_openai_unit_test_env) -> None:
+    with (
+        patch(
+            f"{AzureOpenAISettings.__module__}.{AzureOpenAISettings.__qualname__}.get_azure_openai_auth_token",
+        ) as mock_get_token,
+    ):
+        mock_get_token.return_value = "test_token"
+        azure_text_completion = AzureTextCompletion()
+
+        assert azure_text_completion.client is not None
+        # API key is provided in env var, so the ad_token should be None
+        assert mock_get_token.call_count == 0
+
+
 @pytest.mark.parametrize("exclude_list", [["AZURE_OPENAI_TEXT_DEPLOYMENT_NAME"]], indirect=True)
 def test_init_with_empty_deployment_name(monkeypatch, azure_openai_unit_test_env) -> None:
     monkeypatch.delenv("AZURE_OPENAI_TEXT_DEPLOYMENT_NAME", raising=False)

python/tests/unit/connectors/open_ai/services/test_azure_text_embedding.py

@@ -8,6 +8,7 @@
 
 from semantic_kernel.connectors.ai.embeddings.embedding_generator_base import EmbeddingGeneratorBase
 from semantic_kernel.connectors.ai.open_ai.services.azure_text_embedding import AzureTextEmbedding
+from semantic_kernel.connectors.ai.open_ai.settings.azure_open_ai_settings import AzureOpenAISettings
 from semantic_kernel.exceptions.service_exceptions import ServiceInitializationError
 
 
@@ -74,6 +75,20 @@ def test_azure_text_embedding_init_with_from_dict(azure_openai_unit_test_env) ->
         assert azure_text_embedding.client.default_headers[key] == value
 
 
+def test_azure_text_embedding_generates_no_token_with_api_key_in_env(azure_openai_unit_test_env) -> None:
+    with (
+        patch(
+            f"{AzureOpenAISettings.__module__}.{AzureOpenAISettings.__qualname__}.get_azure_openai_auth_token",
+        ) as mock_get_token,
+    ):
+        mock_get_token.return_value = "test_token"
+        azure_text_embedding = AzureTextEmbedding()
+
+        assert azure_text_embedding.client is not None
+        # API key is provided in env var, so the ad_token should be None
+        assert mock_get_token.call_count == 0
+
+
 @pytest.mark.asyncio
 @patch.object(AsyncEmbeddings, "create", new_callable=AsyncMock)
 async def test_azure_text_embedding_calls_with_parameters(mock_create, azure_openai_unit_test_env) -> None: