[Bufix] Fix None output issue caused by outputs patch (#712)

### What this PR does / why we need it?

Fix None output issue caused by outputs patch


---------

Signed-off-by: MengqingCao <cmq0113@163.com>

Author: MengqingCao

vllm_ascend/patch_outputs.py

@@ -15,6 +15,7 @@
 # limitations under the License.
 #
 
+import time
 from typing import Dict, Optional
 
 from vllm.outputs import CompletionOutput, RequestOutput
@@ -84,7 +85,7 @@ def from_seq_group(
         output_token_ids = seq.get_output_token_ids_to_return(delta)
         num_output_tokens = 1 if isinstance(output_token_ids,
                                             int) else len(output_token_ids)
-        num_cached_tokens = seq.data.get_num_cached_tokens()  # noqa
+        num_cached_tokens = seq.data.get_num_cached_tokens()
 
         output_logprobs = seq.output_logprobs if include_logprobs else None
 
@@ -139,7 +140,44 @@ def from_seq_group(
 
         outputs.append(output)
 
-    return None
+    # Every sequence in the sequence group should have the same prompt.
+    if include_prompt:
+        prompt = seq_group.prompt
+        prompt_token_ids = seq_group.prompt_token_ids
+        encoder_prompt = seq_group.encoder_prompt
+        encoder_prompt_token_ids = seq_group.encoder_prompt_token_ids
+        prompt_logprobs = seq_group.prompt_logprobs
+    else:
+        prompt = None
+        prompt_token_ids = None
+        encoder_prompt = None
+        encoder_prompt_token_ids = None
+        prompt_logprobs = None
+    finished_time = time.time() if finished else None
+    seq_group.set_finished_time(finished_time)
+
+    init_kwargs = {
+        "request_id": seq_group.request_id,
+        "prompt": prompt,
+        "prompt_token_ids": prompt_token_ids,
+        "prompt_logprobs": prompt_logprobs,
+        "outputs": outputs,
+        "finished": finished,
+        "metrics": seq_group.metrics,
+        "lora_request": seq_group.lora_request,
+        "encoder_prompt": encoder_prompt,
+        "encoder_prompt_token_ids": encoder_prompt_token_ids,
+        "num_cached_tokens": num_cached_tokens,
+        "multi_modal_placeholders": seq_group.multi_modal_placeholders
+    }
+
+    if use_cache:
+        request_output = seq_group.cached_request_output
+        request_output.__init__(**init_kwargs)  # type: ignore
+    else:
+        request_output = cls(**init_kwargs)  # type: ignore
+
+    return request_output
 
 
 # Add code to clear finished seq in seq_id_to_seq_group