message: core: fix variable name in lazy plugin
diff: @@ -12,18 +12,18 @@ public:
  Plugin* maybe_plugin()
  {
  - if (_action == nullptr) {
  + if (_plugin == nullptr) {
  if (_mavsdk.systems().empty()) {
  return nullptr;
  }
  - _action = std::make_unique<Plugin>(_mavsdk.systems()[0]);
  + _plugin = std::make_unique<Plugin>(_mavsdk.systems()[0]);
  }
  - return _action.get();
  + return _plugin.get();
  }
  private:
  Mavsdk& _mavsdk;
  - std::unique_ptr<Plugin> _action{};
  + std::unique_ptr<Plugin> _plugin{};
  };
  } // namespace mavsdk::mavsdk_server
  