fix: [vps] make ``vps mongo update`` more resilient

Keeping the cron container, even dormant, will kick back when it'll
awaken as it is still connected to old session dirs that were deleted.

bin/vps

@@ -2741,6 +2741,7 @@ cmdline.spec:mongo:cmd:upgrade:run() {
     cron_container=$(compose:service:containers "${project_name}" "cron")
     containers="$containers $cron_container"
     docker stop "$cron_container" >/dev/null 2>&1 || true
+    docker rm "$cron_container" >/dev/null 2>&1 || true
 
     before_version=
     uptodate=