Feature: #83711 - FeatureFlag: unifiedPageTranslationHandling 

See forge#83711

Description 

The feature switch unifiedPageTranslationHandling is active for all new installations, but not active for existing installations.

It does the following when active:

  • All DB schema migrations decide to drop pages_language_overlay
  • TCA migration no longer throws a deprecation info (but still unsets pages_language_overlay)

Once the Update Wizard for migrating pages_language_overlay records is done, the feature is enabled.