Fix changelog (Azure#49583)

* Fix changelog

* Fix date

Author: nick863

sdk/ai/Azure.AI.Projects/CHANGELOG.md

@@ -1,17 +1,13 @@
 # Release History
 
-## 1.0.0-beta.8 (Unreleased)
+## 1.0.0-beta.8 (2025-04-23)
 
 ### Sample Updates
 * New sample added for connected agent tool.
 
-### Breaking Changes
-
 ### Bugs Fixed
 * Fix for filtering of messages by run ID [see GitHub issue issue 49513](https://github.com/Azure/azure-sdk-for-net/issues/49513).
 
-### Other Changes
-
 ## 1.0.0-beta.7 (2025-04-18)
 
 ### Features Added