Weird AJAX behavior when selecting a setting on the filter format page

Problem/Motivation

Currently, when we go to a text format configuration page and press either "Enable Mentions: Node" or "Enable Mentions: User" an AJAX request is fired, the "Mentions" tab closes, and we end up inside the first "CKEditor 5 plugin settings" tab (usually "Headings").

This only happens on the initial page load, any further checkbox clicking doesn't trigger this behavior anymore.

Steps to reproduce

• Go to e.g. /admin/config/content/formats/manage/full_html.
• Scroll down to the "CKEditor 5 plugin settings", select the "Mentions" Tab and activate a checkbox.
• We end up in the "Headings" Tab after the AJAX request finished.

Proposed resolution

Fix the issue.

Remaining tasks

User interface changes

API changes

Data model changes