Offboarding 'mark as Done' Now Completes Remaining Apps and Tasks

Previously, marking an offboarding as done left open removal tasks and tickets unresolved, causing stale reminders — some dating back to 2020. Now, Mark as done behaves consistently with marking each app done individually:

• Remaining apps are marked completed with an admin attribution, open removal tasks are resolved, and completion notifications are sent to all configured recipients (including via the public API PUT /v1.0/users/{idUser}).
• A confirmation prompt is shown before proceeding — on the user page (showing the count of incomplete apps) and in bulk (showing the count of affected users) — since notifications cannot be undone.