Chore: updated changelog

Author: khatruong2009

packages/amplify/amplify_flutter/CHANGELOG.md

@@ -5,6 +5,7 @@
 
 ### Fixes
 - fix: catch and log updateEndpoint error during configure ([#3985](https://github.com/aws-amplify/amplify-flutter/pull/3985))
+- fix(analytics): event client flush events to do not discard events from cache on auth exception ([#3999](https://github.com/aws-amplify/amplify-flutter/pull/3999))
 
 ## 1.4.1