session: fix goleak in the sendBatchRequest (#31991)
session: fix goleak in the sendBatchRequest (#31991)

close pingcap/tidb#31990
pingcap/tidb,c4pt0r/tidb,pingcap/tidb,pingcap/tidb,kyle-wang/tidb,kyle-wang/tidb,kyle-wang/tidb,ngaut/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb,ngaut/tidb,pingcap/tidb,c4pt0r/tidb,ngaut/tidb,pingcap/tidb,c4pt0r/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,kyle-wang/tidb