Update CHANGELOG to remove peerDependencies section

Removed peerDependencies update for @launchdarkly/server-sdk-ai from CHANGELOG.

Author: jsonbailey

packages/ai-providers/server-ai-langchain/CHANGELOG.md

@@ -8,8 +8,6 @@
 * The following workspace dependencies were updated
   * devDependencies
     * @launchdarkly/server-sdk-ai bumped from ^0.12.2 to ^0.12.3
-  * peerDependencies
-    * @launchdarkly/server-sdk-ai bumped from ^0.12.2 to ^0.12.3
 
 ## [0.1.2](https://github.com/launchdarkly/js-core/compare/server-sdk-ai-langchain-v0.1.1...server-sdk-ai-langchain-v0.1.2) (2025-10-16)