mds: trigger stray reintegration when loading dentry

mds: trigger stray reintegration when loading dentry

During recursive scrub, the MDS will load a remote dentry into cache but
not necessarily check if reintegration is necessary. Before this commit,
it would only happen when the dentry is returned from a client request.
To effect global reintegration when there are too many strays, this
means a cluster admin would have to do `find` on the CephFS file system.
This is unsavory because of the cache / cap explosion involved.

Fixes: https://tracker.ceph.com/issues/53641
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>