mon: osd flag health message is misleading
If any flags of interest are set it issues a warning like
HEALTH_WARN noout,noin,noscrub,nodeep-scrub,sortbitwise,require_jewel_osds flag(s) set
but that include all flags, not just the interesting ones, which is confusing for the admin.
Note that later in a ceph -s output we still see all flags, so we should just show the interesting ones here.