Summary:
Fix a crash that occurs when locking rows in temporary tables due to incorrect transaction xid cleanup.

Set YbSetTxnUsesTempRel() when locking rows in temporary tables, consistent with how we handle other temporary table operations. This ensures the transaction is cleanly recorded and committed.

Note: Currently, the behaviour for transactions involving both regular tables and temporary tables is not well defined in YB. However, this isn't an issue for row-level locking because we already disallow mixing YB-backed and non-YB-backed relations (such as temp tables).
Jira: DB-16633

Test Plan: ./yb_build.sh release  --java-test 'org.yb.pgsql.TestPgRegressFeature'

Reviewers: kramanathan, #db-approvers

Reviewed By: kramanathan

Subscribers: svc_phabricator, yql

Differential Revision: https://phorge.dev.yugabyte.com/D44368