Only decode JSON input buffer in Anthropic Claude streaming (open-telemetry#3875)

* Only decode JSON input buffer in Anthropic Claude streaming

_decode_tool_use was only used when _tool_json_input_buf was found, but we were decoding the entire _content_block after adding _tool_json_input_buf to it. The _content_block overall which could contain non-JSON elements (e.g. {}), causing failures. To fix this, we have removed _decode_tool_use helper function and inlined JSON decoding logic directly into content_block_stop handler in _process_anthropic_claude_chunk, where we only use it to decode _tool_json_input_buf before appending to _content_block.

* Update test_botocore_bedrock.py

Fix lint: `opentelemetry-instrumentation-botocore/tests/test_botocore_bedrock.py:2990:4: C0415: Import outside toplevel (opentelemetry.instrumentation.botocore.extensions.bedrock_utils.InvokeModelWithResponseStreamWrapper) (import-outside-toplevel)`

* Update test_botocore_bedrock.py

Remove extra line

* fix lint issue

Author: thpierce

CHANGELOG.md

@@ -40,6 +40,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `opentelemetry-exporter-richconsole`: Prevent deadlock when parent span is not part of the batch
   ([#3900](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3900))
 
+### Fixed
+
+- `opentelemetry-instrumentation-botocore`: Handle dict input in _decode_tool_use for Bedrock streaming
+  ([#3875](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3875))
+
 ## Version 1.38.0/0.59b0 (2025-10-16)
 
 ### Fixed