osd/OSD: Query osd op queue type from scheduler instead of config subsystem

osd/OSD: Query osd op queue type from scheduler instead of config subsystem

All OSD shards are guaranteed to use the same scheduler type. Therefore,
OSD::osd_op_queue_type() is used where applicable to determine the
scheduler type. This results in the appropriate setting of other config
options based on the randomly selected scheduler type in case the global
'osd_op_queue' config option is set to 'debug_random' (for e.g., in CI
tests).

Note: If 'osd_op_queue' is set to 'debug_random', the PG specific code
(PGPeering, PrimaryLogPG) would continue to use the existing mechanism of
querying the config option key (osd_op_queue) as before using get_val().

Fixes: https://tracker.ceph.com/issues/62171
Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>