Enable support for Android per-app language preferences

[tonkku107]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

This PR does the few changes necessary to support this system feature on Android 13 and newer devices. This does not add in-app language settings or a method for Android 12 and older users to set a per-app language, but this can be done later using androidx.appcompat APIs.

Motivation and context

Users would like to set a different language than their system default for Element X. This PR would at least allow users with Android 13 or newer to use their system settings to change the language to their preferences until (and after) an in-app UI is created.

Screenshots / GIFs

Tests

• Installed debug build
• Opened app info
• Checked that the language settings existed
• Checked that switching to another language (for example German) also reflected to a change in language in-app
• Made sure the app still works on API 23, and nothing has changed

Tested devices

• Physical
• Emulator
• OS version(s): 15 (Beta 1.2), 6

Checklist

• Changes have been tested on an Android device or Android emulator with API 23
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request includes a new file under ./changelog.d. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#changelog
• Pull request includes screenshots or videos if containing UI changes
• Pull request includes a sign off
• You've made a self review of your PR

I would like to sign-off privately.

[github-actions]

Thank you for your contribution! Here are a few things to check in the PR to ensure it's reviewed as quickly as possible:

• Your branch should be based on origin/develop, at least when it was created.
• There is a changelog entry in the changelog.d folder with the Towncrier format.
• The test pass locally running ./gradlew test.
• The code quality check suite pass locally running ./gradlew runQualityChecks.
• If you modified anything related to the UI, including previews, you'll have to run the Record screenshots GH action in your forked repo: that will generate compatible new screenshots. However, given Github Actions limitations, it will prevent the CI from running temporarily, until you upload a new commit after that one. To do so, just pull the latest changes and push an empty commit.

[jmartinesp]

Thanks, this is something that would have been useful to implement to verify issues in different languages but it was never a priority to build, so it's perfect that's done in an external contribution!