chore: Follow up homeserver input field

lib/pages/homeserver_picker/homeserver_picker.dart

@@ -80,7 +80,9 @@ class HomeserverPickerController extends State<HomeserverPicker> {
   }
 
   void onSubmitted([_]) {
-    if (isLoading) return tryCheckHomeserverActionWithoutCooldown();
+    if (isLoading || _checkHomeserverCooldown?.isActive == true) {
+      return tryCheckHomeserverActionWithoutCooldown();
+    }
     if (supportsSso) return ssoLoginAction();
     if (supportsPasswordLogin) return login();
     return tryCheckHomeserverActionWithoutCooldown();