feat: implement thread-safe image saving with mutex and update save logic

orbbec_camera/include/orbbec_camera/ob_camera_node.h

@@ -809,6 +809,7 @@ class OBCameraNode {
   std::unique_ptr<D2CViewer> d2c_viewer_ = nullptr;
   std::map<stream_index_pair, std::atomic_bool> save_images_;
   std::map<stream_index_pair, int> save_images_count_;
+  std::mutex save_images_mutex_;
   int max_save_images_count_ = 10;
   std::atomic_bool save_point_cloud_{false};
   std::atomic_bool save_colored_point_cloud_{false};