mgr/cephadm: only add deps for set NFS spec fields, skip upgrade reconfig for defaults

Only add deps when the user has set a non-default value.  In
choose_next_action(), ignore False/None-valued entries in the symmetric
diff so daemons upgrading from the old behavior are not reconfigured
solely because default deps disappeared

Fixes: https://tracker.ceph.com/issues/77901
Signed-off-by: Shweta Bhosale <Shweta.Bhosale1@ibm.com>