As soon as the label of the current interface language is being updated the title in the vector-page-titlebar gets updated.
As soon as the change is saved the page title (shown next to favicon) is also updated.
The title shown in the vector-sticky-header is however not updated until the page is reloaded. Since this covers the vector-page-titlebar on scroll this leads to a weird situation where the title seems to revert.

Expected behaviour would be for the title shown in the sticky header to be updated at the same time as the title in the vector-page-titlebar (in case the user scrolls the page before committing the label change). It would however likely be acceptable to only update it when the label change is committed (similar to how the page title shown next to the favicon is treated).

Steps to reproduce:

• Load https://www.wikidata.org/wiki/Q4115189?useskin=vector-2022&uselang=en
• Start editing the English label and observe that the heading already updates before saving
• Scroll down and observe that the sticky header still has the outdated label
• Save the edit and observe the same behaviour of the two headers

Acceptance criteria:

• When editing the label of an item in the Vector 2022 skin, the sticky header is updated with the new label, just like the regular heading is already updated.
• If the sticky header ever appears on properties, then it should be updated there too (but it seems that this might not be the case – is the sticky header restricted to the main namespace?). Lexemes, EntitySchema and MediaInfo entities are not affected.