fix(core): improve channel messages pagination logic (#2284)

Author: xsahil03x

packages/stream_chat_flutter_core/CHANGELOG.md

@@ -1,3 +1,10 @@
+## Upcoming
+
+🐞 Fixed
+
+- Fixed pagination end detection logic to properly determine when the top or bottom of the message
+  list has been reached.
+
 ## 9.12.0
 
 ✅ Added