Merge PR #51539 into main

* refs/pull/51539/head:
	doc: users now need to provide scrub_mdsdir and recursive flags
	qa: add recursive flag to test_flag_scrub_mdsdir
	mds: remove code to bypass dumping empty header scrub info
	mds: dump_values no more needed
	mds: enqueue ~mdsdir at the time of enqueing root

Reviewed-by: Venky Shankar <vshankar@redhat.com>

diff --cc qa/tasks/cephfs/test_scrub_checks.py
Simple merge

diff --cc src/mds/MDCache.cc
Simple merge

diff --cc src/mds/MDSRank.cc
Simple merge