* Cleans up all root level temp., snap-%s.dat, meta-%s.dat blobs that aren't referenced by any snapshot to deal with dangling blobs left behind by delete and snapshot finalization failures
* The scenario that get's us here is a snapshot failing before it was finalized or a delete failing right after it wrote the updated index-(N+1) that doesn't reference a snapshot anymore but then fails to remove that snapshot
* Not deleting other dangling blobs since that don't follow the snap-, meta- or tempfile naming schemes to not accidentally delete blobs not created by the snapshot logic
* Follow up to #42189
* Same safety logic, get list of all blobs before writing index-N blobs, delete things after index-N blobs was written
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