fix tests.backup_test.BackupTest.test_backup_with_less_privileges_role @ PG-15

Author: kulaginm

tests/backup_test.py

@@ -2126,7 +2126,6 @@ def test_backup_with_less_privileges_role(self):
         if self.get_version(node) >= 150000:
             node.safe_psql(
                 'backupdb',
-                "BEGIN; "
                 "CREATE ROLE backup WITH LOGIN; "
                 "GRANT USAGE ON SCHEMA pg_catalog TO backup; "
                 "GRANT EXECUTE ON FUNCTION pg_catalog.current_setting(text) TO backup; "