Backup Management: Disable 'Restore' button for backups whose service has been deleted

After backing up from a service, users might later on delete that same service.
In that case, it's not possible to restore that backup to the same service, but only to a compatible one.
Thus, the frontend has to check if a given backup is missing its service ID or service name. If so, the restore button within the modal has to be blocked and the user must be warned about it, so that they know they must pick a compatible service.

How to test

• Create a backup from a service;
• When the backup is complete, delete that same service;
• Try to restore that backup: the "restore" button should be disabled and there must an error below the buttons.