Make OG Menu Drupal 12 compatible

Problem/Motivation

Drupal 12 is scheduled to be released this year (2026). One of the tests I wrote at the Babel contrib (see this message at the related CI job) revealed that OG Menu has at least one incompatible component which needs alignment to be compatible with the next release (at the time I'm writing this ticket).

Proposed resolution

Make Organic Groups Menu compatible with Drupal 12.

Remaining tasks

User interface changes

Nothing.

API changes

Nothing.

Data model changes

Nothing.