enh(a11y): Add accessible user menu semantics

[Pytal]

• For [BITV] 9.4.1.2/2.3 - The "Open settings menu" menu - The aria-expanded attribute was correctly applied to the menu button, but the attribute always has the value "true" which is incorrect. (9) #37095

Summary

• Wrap menu trigger button in nav container
• Add distinct label to app menu navigation landmark
• Add user status to accessible name i.e. "Avatar of John — Online — 📅 — In a meeting"
• Test with NVDA

No visual changes

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[susnux]

Agree the the note of @ShGKme but otherwise looks fine

[JuliaKirschenheuter]

looks good, thank you!

[Pytal]

Otherwise we're good to go

[Pytal]

CI failures unrelated