Extract cloud download thread launcher

src/legacy_cloud_services.cpp

@@ -176,6 +176,15 @@ void execute_cloud_download_thread(
     pp::panopainter::close_legacy_dialog_node(*m);
 }
 
+void launch_cloud_download_thread(
+    App& app,
+    const pp::app::CloudDownloadRequest& request)
+{
+    std::thread([app = &app, request] {
+        execute_cloud_download_thread(*app, request);
+    }).detach();
+}
+
 void execute_cloud_publish_worker(App& app, bool save_before_upload)
 {
     BT_SetTerminate();
@@ -318,10 +327,7 @@ public:
 
     void start_download(const pp::app::CloudDownloadRequest& request) override
     {
-        auto* app = &app_;
-        std::thread([app, request] {
-            execute_cloud_download_thread(*app, request);
-        }).detach();
+        launch_cloud_download_thread(app_, request);
     }
 
 private: