major refactor

lib/components/login/login.dart

@@ -151,6 +151,13 @@ class _LoginPanelContentState extends State<LoginPanelContent> {
 
   bool _loggingIn = false;
 
+  @override
+  void dispose() {
+    _usernameController.dispose();
+    _passwordController.dispose();
+    super.dispose();
+  }
+
   Future<void> login() async {
     final username = _usernameController.text;
     final password = _passwordController.text;