Draft: ISSUE-52985: [hideMenu-isNewUI] Assume isNewUI==true

Issue https://issues.openbravo.com/view.php?id=13891 started hiding some bits of full 2.50 old UI when running in new UI.

With 3.0 / newUI being the only & default now it is no longer useful to run the full old 2.50 UI (see issue for a screenshot

Assume that is never wanted/useful and cleanup the code accordingly.

TODO:

• Reference https://issues.openbravo.com/view.php?id=52985
  • either squash commits on merge
  • or add merge commit for it
• try: https://builds.openbravo.com/view/try/job/try-init/2400/