fix(add-tailscale-lxc): stop spinner before whiptail menu (#16402)

msg_info starts a background spinner while loading the container list,
but the script never stops it before opening the interactive radiolist,
so the spinner keeps repainting over the UI.

Co-authored-by: Cursor <cursoragent@cursor.com>

tools/addon/add-tailscale-lxc.sh

@@ -57,6 +57,7 @@ while read -r line; do
   CTID_MENU+=("$TAG" "$ITEM" "OFF")
 done < <(pct list | awk 'NR>1')
 
+stop_spinner
 CTID=""
 while [[ -z "${CTID}" ]]; do
   CTID=$(whiptail --backtitle "Proxmox VE Helper Scripts" --title "Containers on $NODE" --radiolist \