Needed setstate in message_feed IconButton in message list page

[Vishnukumardev]

I was going to try to solve an issue and I happen to saw it making errors while tapping on the message feed .It is an feature used to saw only the messages that are associated with sticky header.To recreate this issue tap on the message feed icon ,It will arise setstate error.Nothing to much and not needed any pull request just add setstate or ui updation code in that place.

Widgets/message_list.dart. Line : 247

Add a setstate that it.

error: [ +31 ms] Another exception was thrown: setState() or markNeedsBuild() called when widget tree was locked. [ +27 ms] Another exception was thrown: setState() or markNeedsBuild() called when widget tree was locked.