Fix known keyboard navigation bugs

[asoucar]

Explicitly adding the focusable field to the RecipientSelectView allows it to be navigated through via arrow keys.
Explicitly adding the focusable field to the Floating Action Button for Compose adds it to the tab navigation. Moving it to the first child of the parent Layout Coordinator allows for it to be focused before the messages in the list while retaining its position. I will say the focus on the compose button is very faint and hard to see. It may be worth investigating during a future refactor
Using Ctrl-Tab shifts tab focus to the top navigation bar and its assorted buttons.

Fixes #8230, #5852
Edit: Removed #8321 from fixes list as it appears to work locally but did not work on some Samsung devices, which I don't have access to for testing

[kewisch]

I'm able to confirm #8230 is solved, it is possible to focus the compose button with Shift+Tab as you mentioned. I'd say it is still not ideal, if you shift tab once too often you end up in the middle of the list and there is no way to get back to the compose button aside from going all the way up again. I'm not very familar with tab navigation on Android, but would it be reasonable behavior that Ctrl+Tab switches between toolbar, message list and compose button?

#8231 is still an issue for me. I am in the compose screen and can tab forward from the "From" line to the "To" line, but from there I cannot get to the subject or message text. I tried both tabbing forward and the arrow keys. My setup is an Apple Magic Keyboard connected via USB to a Samsung device. Did I miss anything here?

Confirming also #5852 is fixed with Ctrl+Tab.

[asoucar]

I'm able to confirm #8230 is solved, it is possible to focus the compose button with Shift+Tab as you mentioned. I'd say it is still not ideal, if you shift tab once too often you end up in the middle of the list and there is no way to get back to the compose button aside from going all the way up again. I'm not very familar with tab navigation on Android, but would it be reasonable behavior that Ctrl+Tab switches between toolbar, message list and compose button?

#8231 is still an issue for me. I am in the compose screen and can tab forward from the "From" line to the "To" line, but from there I cannot get to the subject or message text. I tried both tabbing forward and the arrow keys. My setup is an Apple Magic Keyboard connected via USB to a Samsung device. Did I miss anything here?

For #8231 I tested this on several emulators with no issue, including the device configuration mentioned in the bug. I don't have a physical Samsung device to test on. If this is an issue that is reacting differently between emulators and device I can remove it from the ticket as I have no way to test it.
For #8230 you are right, enough tab/ctrl-tab can lose you access to the compose button. The issue is the view hierarchy. When you Ctrl-tab the toolbar is the parent view to both the message list and the compose button so you can't just jump between them. I will see if I can adjust the hierarchy to fix this, but more likely this would require a large refactor of the view

[asoucar]

@kewisch I was not able to simply restructure the views to get the floating compose button to be always quickly reachable via tab unfortunately. I think a larger restructure will be necessary. I think it is worth merging this fix for what it does and make a note of the rest for future work.
I am also removing #8231 from the fixes list as I cannot reproduce with my current emulator setup.

[kewisch]

Sounds good, thanks for checking!

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