Mute ydb/core/kqp/ut/olap KqpOlap.ManyColumnShards (#8782)

Author: naspirato

.github/config/muted_ya.txt

@@ -103,3 +103,5 @@ ydb/tests/functional/tenants test_tenants.py.*
 ydb/tests/functional/ydb_cli test_ydb_impex.py.TestImpex.test_big_dataset*
 ydb/tests/tools/pq_read/test test_timeout.py.TestTimeout.test_timeout
 ydb/core/kqp/ut/query KqpStats.SysViewClientLost
+ydb/core/kqp/ut/olap KqpOlap.ManyColumnShards
+