Merge PR #53989 into wip-rishabh-testing-20250426.123842-debug

* refs/pull/53989/head:
	qa: test empty string arg during subvol create
	doc: new CephString attribute 'allowempty'
	mgr/volumes: tag args with allowempty=false
	pybind: add 'allowempty' as a CephString attribute
	qa: don't pass spurious empty string in lieu of subvol options

Reviewed-by: Rishabh Dave <ridave@redhat.com>

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

diff --cc src/pybind/ceph_argparse.py
Simple merge

diff --cc src/pybind/mgr/volumes/module.py
Simple merge