Fixed unit test ManyColumnShards (#8777)

Author: GrigoriyPA

ydb/core/kqp/ut/olap/kqp_olap_ut.cpp

@@ -1432,6 +1432,8 @@ Y_UNIT_TEST_SUITE(KqpOlap) {
         Tests::TServer::TPtr server = new Tests::TServer(settings);
 
         auto runtime = server->GetRuntime();
+        runtime->SetScheduledLimit(1000000);
+
         auto sender = runtime->AllocateEdgeActor();
 
         InitRoot(server, sender);