mgr/vol: count number of ongoing clones in CloneProgressReporter...
instead of relying on the config value "mgr/volumes/max_concurrent_clones".
This reliance is not really needed since CloneProgressReporter goes
through all clone entries and collect info about every clone anyways. If
it takes one more step to get clone state it wouldn't need to reply on
this config option.
Fixes: https://tracker.ceph.com/issues/67987 Signed-off-by: Rishabh Dave <ridave@redhat.com>