Enhancement: Clear removed snapshots from local cache of the current host

Restic only removed snapshots from the cache on the host that runs the `forget` command.
On other hosts that use the same repository, the old snapshots remained in the cache.
Restic now, automatically clears old snapshots from the local cache of the current host.

https://github.com/restic/restic/issues/4934
https://github.com/restic/restic/pull/4981