fix(NcAppSidebar): move focus to sidebar on open and auto return focus on close

[ShGKme]

☑️ Resolves

• Fix for [BITV] 9.2.4.3/3.3 - When opening the "Details" section through the "Actions" menu in the table, the keyboard focus is not shifted to the details view; instead, it is moved to the beginning of the next row of the table. (1) nextcloud/server#41877
• Can be tested with fix(files): move focus to sidebar on open nextcloud/server#42444

See description in commits.

Screenshots

On desktop

1. Open sidebar
2. Focus is moved to the sidebar
3. Close sidebar
4. Focus is moved to the trigger button
5. For menu - special case, return to the menu trigger

sidebar-focus-desktop.mp4

On mobile with focus-trap - also works

sidebar-focus-mobile.mp4

When sidebar was open, but a new file or tab was selected — focus is moved to the tab, and the element to return is updated

sidebar-focus-after-open.mp4

When the sidebar is initially open on page load - no focus move

sidebar-focus-on-load.mp4

Also works for apps

sidebar-focus-apps.mp4

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable

[ShGKme]

Checking Cypress

[Pytal]

Other than minor comments, nice!

[ShGKme]

Checking Cypress

<Transition> didn't work, <transition> works.

[JuliaKirschenheuter]

works great! Thanks a lot!