Update CHANGELOG.md

Author: wyf7107

CHANGELOG.md

@@ -5,7 +5,6 @@
 
 ### Bug Fixes
 
-* cherry-pick bug fixes from main into v1 ([d22291d](https://github.com/google/adk-python/commit/d22291d4d68d99704ff25aa697bdfd6dbfd3eb60))
 * Fix bug where grounding metadata in Gemini 3.1 live was being silently discarded ([9b6b9e9](https://github.com/google/adk-python/commit/9b6b9e976300ab223c77075554d6cd66ce1179ff))
 * fix input and output transcription finished events for Gemini v3.1 ([13763d7](https://github.com/google/adk-python/commit/13763d71f883b215dae08feb3f042869b9cd5d18))
 * **tools:** Prevent session drop on MCP tool error ([1fd406b](https://github.com/google/adk-python/commit/1fd406b90ae00c59d84093c33bc04530825bc760))