Description
After #11209
Migrate key backups keys from the key backup metadata to SSSS. I don't think we need to delete them from the key backup metadata: that would involve deleting & recreating the key backup. I don't think having in both places is a problem.
For now I'm saying we do this at key backup restore time, although this is just about getting the code written and deployed: it will later become part of the integrated security setup process.