Implement websocket

lib/services/authentication_manager.dart

@@ -199,4 +199,12 @@ class AuthenticationManager extends ChangeNotifier {
       slot: slot,
     );
   }
+
+  Future<void> dropAutoStaticGroup(int dmrId) async {
+    if (_client == null) {
+      throw BrandmeisterError('Not authenticated');
+    }
+
+    await _client!.dropAutoStaticGroup(dmrId);
+  }
 }