Improve ServerChooser UI and use server avatar

[TimoPtr]

Summary

This PR refactor the ServerChooser to be more modern and migrate to our new theme. While at it this PR also add the avatar of the server and make the bottom sheet more friendly.

Checklist

• New or updated tests have been added to cover the changes following the testing guidelines.
• The code follows the project's code style and best_practices.
• The changes have been thoroughly tested, and edge cases have been considered.
• Changes are backward compatible whenever feasible. Any breaking changes are documented in the changelog for users and/or in the code for developers depending on the relevance.

Screenshots

Any other notes

This is based on #6989

[jpelgrom]

This PR is also changing quite a lot in the deeplink handling which doesn't seem completely necessary (keep the PR small). Is it possible to split the changes?

[jpelgrom]

The active checkmark always appears to be added to the sheet, but I'm not sure this makes sense in situations where the active server is unclear to the user, so when used outside the webview context when opening links or syncing Thread credentials from settings.

[TimoPtr]

This PR is also changing quite a lot in the deeplink handling which doesn't seem completely necessary (keep the PR small). Is it possible to split the changes?

It doesn't change the deep link it adds a viewModel to extract the logic out of the activity. Do you want a dedicated PR that introduce the viewModel?

[TimoPtr]

The active checkmark always appears to be added to the sheet, but I'm not sure this makes sense in situations where the active server is unclear to the user, so when used outside the webview context when opening links or syncing Thread credentials from settings.

Actually it is helpful for people that have the same name on two servers that have the same username. So you know which one is the currently activated.

[jpelgrom]

The server chooser waits for network requests to complete before showing servers. If a server is offline or slow to reach, you may be waiting up to okhttp's network timeout for that to happen. This shouldn't happen; any network requests to load the image should be async to showing the actual sheet.

Simulated example with 5s:

delay-server.mp4

[jpelgrom]

Everything here feels a bit too big to me, but maybe that is personal preference. Material 3 guidelines for a two-line list suggest 72dp min height (vs 80dp), 40dp avatar size (vs 48dp).