fix(android): use the active locale to detect RTL direction

[zoontek]

Summary:

On Android, RTL detection read the wrong locale. isDevicePreferredLanguageRTL use Locale.getAvailableLocales()[0], which returns an arbitrary entry from the unordered list of all runtime locales (so, all locales that the current Android version supports), not the user's current system / app language. So layout direction was resolved from whatever locale happened to be first in that list, unrelated to the device (or per-app) language.

This fixes it to read the active locale from context.resources.configuration.locales[0], the resolved preferred locale for the app.

See the screenshots below: Locale.getAvailableLocales()[0] returns all locales supported by Android, so the first one is always af, and isRTL is always false:

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vs context.resources.configuration.locales[0] for the same device language (I chose ar-JO in app settings), isRTL is true:

Changelog:

[ANDROID] [FIXED] - Detect RTL from the active locale instead of an arbitrary installed one

Test Plan:

Switch the device (or per-app) language to an RTL language (e.g. Arabic) and confirm the app lays out RTL.

Locale.getAvailableLocales()[0] (before, arbitrary):

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context.resources.configuration.locales[0] (after, active locale):

[meta-codesync]

@Abbondanzo has imported this pull request. If you are a Meta employee, you can view this in D113244807.