Fixed PropertyNameHelper test (uppercase-output)

Summary: Adds to D17: Had to change the property name helper test in order to follow the new DICOM uppercase character standard.

Test Plan: Unit test contained; was modified corresponding to the changes made to the module itself

Reviewers: floca, kislinsk, O1 MITK Core

Reviewed By: kislinsk, O1 MITK Core

Subscribers: kalali

Maniphest Tasks: T22064

Differential Revision: https://phabricator.mitk.org/D18