fix: state management for signature method and code challenge method in OAuth fields

Author: Udhay-Adithya

lib/screens/common_widgets/auth/oauth1_fields.dart

@@ -130,7 +130,9 @@ class _OAuth1FieldsState extends ConsumerState<OAuth1Fields> {
               ? null
               : (OAuth1SignatureMethod? newAlgo) {
                   if (newAlgo != null) {
-                    _signatureMethodController = newAlgo;
+                    setState(() {
+                      _signatureMethodController = newAlgo;
+                    });
                     _updateOAuth1();
                   }
                 },

lib/screens/common_widgets/auth/oauth2_field.dart

@@ -256,7 +256,9 @@ class _OAuth2FieldsState extends ConsumerState<OAuth2Fields> {
                 : (String? newMethod) {
                     if (newMethod != null &&
                         newMethod != _codeChallengeMethod) {
-                      _codeChallengeMethod = newMethod;
+                      setState(() {
+                        _codeChallengeMethod = newMethod;
+                      });
 
                       _updateOAuth2();
                     }