[pg] Fix commit insert into two tables

[rekby]

Run local ydb

echo "
DROP TABLE IF EXISTS t1;
DROP TABLE IF EXISTS t2;
CREATE TABLE t1 (id INT NOT NULL, PRIMARY KEY (id)); 
CREATE TABLE t2 (id INT NOT NULL, PRIMARY KEY (id)); 

BEGIN; 
INSERT INTO t1 (id) VALUES (1); 
INSERT INTO t2 (id) VALUES (2); 
COMMIT;
" | psql postgres://root:1234@localhost:5432/local

Error:

Status: INTERNAL_ERROR
Issues:
<main>: Error: ydb/core/kqp/executer_actor/kqp_executer_impl.cpp:98  CreateKqpExecuter(): requirement *txsType == NKqpProto::TKqpPhyTx::TYPE_DATA failed, message: Cannot execute multiple non-data physical txs.```


Expected behaviour: insert two values into tables

[gridnevvvit]

issue was fixed in #2919