24-3: Check shard state at TTxCdcStreamEmitHeartbeats (#7148)

Author: CyberROFL

ydb/core/tx/datashard/cdc_stream_heartbeat.cpp

@@ -33,6 +33,10 @@ class TDataShard::TTxCdcStreamEmitHeartbeats: public NTabletFlatExecutor::TTrans
     TTxType GetTxType() const override { return TXTYPE_CDC_STREAM_EMIT_HEARTBEATS; }
 
     bool Execute(TTransactionContext& txc, const TActorContext&) override {
+        if (Self->State != TShardState::Ready) {
+            return true;
+        }
+
         LOG_I("Emit change records"
             << ": edge# " << Edge
             << ", at tablet# " << Self->TabletID());