fix(kqp): always take snapshot for queries with stream lookup

Author: ulya-sidorina

ydb/core/kqp/common/kqp_tx.cpp

@@ -184,6 +184,11 @@ bool NeedSnapshot(const TKqpTransactionContext& txCtx, const NYql::TKikimrConfig
         return true;
     }
 
+    // We always need snapshot for stream lookup, besause it's used for dependent reads
+    if (hasStreamLookup) {
+        return true;
+    }
+
     // We don't want snapshot when there are effects at the moment,
     // because it hurts performance when there are multiple single-shard
     // reads and a single distributed commit. Taking snapshot costs