openai-v2: add CHANGELOG entry for #4455

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: nagkumar91

instrumentation-genai/opentelemetry-instrumentation-openai-v2/CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Import `OTEL_INSTRUMENTATION_GENAI_CAPTURE_MESSAGE_CONTENT` from
+  `opentelemetry.util.genai.environment_variables` instead of re-defining it locally,
+  making `opentelemetry-util-genai` the single source of truth for this constant.
+  ([#4455](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4455))
+
 - Fix `ChoiceBuffer` crash on streaming tool-call deltas with `arguments=None`
   ([#4350](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4350))
 - Fix `StreamWrapper` missing `.headers` and other attributes when using `with_raw_response` streaming