fix update

update

@@ -36,8 +36,9 @@ install_backend_and_download_resources() {
                         download_and_unzip "https://github.com/jxxghp/MoviePilot-Frontend/releases/download/${frontend_version}/dist.zip" "dist"
                         if [ $? -eq 0 ]; then
                             echo "前端程序下载成功"
-                            rm -rf /app
-                            mv /tmp/App /app
+                            find /app/* -type d ! -path "/app/app/plugins" -exec rm -rf {} \;
+                            find /app/* -type f ! -path "/app/app/plugins/*" -exec rm -f {} \;
+                            mv -f /tmp/App/* /app/
                             rm -rf /public
                             mv /tmp/dist /public
                             mv -f /tmp/Plugins/plugins/* /app/app/plugins/