Wrong tab-order after opening or editing a wiki page

[krallowski]

Accessibility: If I use the keyboard to open or edit the page and then hit "tab" again, the focus is not as expected at the next element for the loaded content. It is set to the profile picture on the top left. So I need to tab through the whole previous content again.
Link to BITV: https://bitvtest.de/pruefschritt/bitv-20-web/bitv-20-web-9-2-4-3-schluessige-reihenfolge-bei-der-tastaturbedienung

Steps to reproduce the issue

1. Press tab to select a page and hit enter
2. The page opens
3. Press tab again

[yurabakhtin]

@luke- PR humhub/humhub#8416