Some storage_service rpc verbs may checks that a handler is executed
inside gossiper scheduling group. For that, the expected group is
grabbed from database.
This patch puts the gossiper sched group into debug namespace and makes
this check use it from there. It removes one more place that uses
database as config provider.
Refs #28410
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#28427