Fix :pivot-measures with column names (#49575) (#49614)

* Fix :pivot-measures with column names

* Fix the test

* Update src/metabase/query_processor/pivot.clj



* Add a test

* Add a test

---------

Co-authored-by: Alexander Polyankin <alexander.polyankin@metabase.com>
Co-authored-by: Braden Shepherdson <braden@metabase.com>