fix(pelican-panel): create backup subdirectory before copying storage

The update script tried to cp into /opt/backup/storage/app/ before
the directory existed, causing a 'Not a directory' error when
/opt/backup was previously a file or the subdirs were missing.
Add mkdir -p to ensure the target directory exists.

Fixes: #14268

ct/pelican-panel.sh

@@ -46,6 +46,7 @@ function update_script() {
     msg_ok "Stopped Service"
 
     cp -a /opt/pelican-panel/.env /opt/backup
+    mkdir -p /opt/backup/storage/app/
     cp -a /opt/pelican-panel/storage/app/public /opt/backup/storage/app/
     
     SQLITE_INSTALL=$(ls /opt/pelican-panel/database/*.sqlite 1>/dev/null 2>&1 && echo "true" || echo "false")