rgw/notify: fix reading the entries in a loop

If more than 1024 entries exist, the start_after variable
is updated to enable reading the subsequent set of entries.

Fixes: https://tracker.ceph.com/issues/73812

Signed-off-by: N Balachandran <[email protected]>

Author: nbalacha

src/rgw/driver/rados/rgw_notify.cc

@@ -127,6 +127,9 @@ class Manager : public DoutPrefixProvider {
         return ret;
       }
       queues.merge(queues_chunk);
+      if (more) {
+        start_after = *queues.rbegin();
+      }
     }
     return 0;
   }