Dispose email and password controllers in the login screen (#2741)

This PR ensures proper disposal of the TextEditingController instances
for the email and password fields in the login screen to prevent memory
leaks.


## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I have added sample code updates to the [changelog].
- [x] I updated/added relevant documentation (doc comments with `///`).

Co-authored-by: Eric Windmill <eric@ericwindmill.com>

Author: sanjidbillah

compass_app/app/lib/ui/auth/login/widgets/login_screen.dart

@@ -43,6 +43,8 @@ class _LoginScreenState extends State<LoginScreen> {
 
   @override
   void dispose() {
+    _email.dispose();
+    _password.dispose();
     widget.viewModel.login.removeListener(_onResult);
     super.dispose();
   }