Conflict resolution code uses constraint name instead of index name

[aafemt]

https://github.com/FirebirdSQL/firebird/blame/95442bdfff76d22aafb57b58894047be2a89c6ea/src/jrd/replication/Applier.cpp#L637

If these names are different debug build consistently throw assertion error during execution of test_blob_not_found_in_rw_replica_if_target_row_exists.py.