[!!!][TASK] Remove Extbase mode for non-consistentTranslationOverlayHandling

The feature flag and all its logic for not using the
consistentTranslationOverlayHandling in Extbase has been removed.

Along with that, QuerySettings interface has two methods less to implement:
- setLanguageMode()
- getLanguageMode()

The methods are kept within the implementation in Typo3QuerySettings without
any actions for now.

Resolves: #87264
Releases: master
Change-Id: Id4f46c8ff61ec86697d8b9dcbe6cd489b2782c0d
Reviewed-on: https://review.typo3.org/59255


Reviewed-by: Alexander Schnitzler <typo3@alexanderschnitzler.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>