[BUG] ContentUsedOnPage incorrectly marks translated container children as "unused" when tx_container_parent points to translated container

[webit-fuchs-julian]

1. Bug description

In the TYPO3 backend Page module, when a specific language is selected (single-language / language comparison view), translated container children are incorrectly shown in the "Unused Elements" section even though they are correctly placed inside their translated container. The frontend renders them correctly.

2. Steps to reproduce

1. Create a page with a container element (e.g. two-column layout) containing child content elements in the default language (lang-0)
2. Translate the page to a non-default language in connected mode — using an extension like thieleundklose/autotranslate or any mechanism that results in translated child records where tx_container_parent points to the translated container UID (lang-N) rather than the lang-0 container UID
3. Open the page in the TYPO3 backend Page module and select the non-default language
4. The translated container children appear in the yellow "Unused Elements" warning box at the bottom of the page

3. Expected behavior

Translated container children that are correctly linked to their translated container should not appear as unused.

4. Affected versions:

3.2.3 (and likely other versions)