test(dsrepl): wait for whole cluster readiness

To minimize the chance of flaky tests due to the shards not being
completely online.

Co-Authored-By: Thales Macedo Garitezi <thalesmg@gmail.com>

apps/emqx_durable_storage/test/emqx_ds_replication_SUITE.erl

@@ -52,7 +52,7 @@ t_replication_transfers_snapshots(Config) ->
     ?retry(
         500,
         10,
-        ?assertMatch([_], shards_online(Node, ?DB))
+        ?assertMatch([[_], [_], [_]], [shards_online(N, ?DB) || N <- Nodes])
     ),
 
     %% Stop the DB on the "offline" node.