fix: use the first available locale to decide directionality on Android

[PRESIDENT810]

Summary:

On iOS, if the default locale is not supported in the app, it will fall back to the first available locale to decide if RTL layout should be enabled or not; however on Android, we use the default locale. So if the first locale is a RTL locale and not supported by the app on Android, the app will fall back to the first available locale which might not be RTL, but the layout would be decided as RTL according to the default locale.

Changelog:

[ANDROID] [FIXED] - use the first available locale instead of the default one to decide isDevicePreferredLanguageRTL

Test Plan:

I set my phone's locale to this order: Hebrew, English and enabled RTL layout:

import { I18nManager } from 'react-native';

I18nManager.allowRTL(true);
I18nManager.swapLeftAndRightInRTL(true);

Prior to my PR, the app would use RTL layout with English on Android which doesn't make much sense (iOS is LTR + English). With my PR Android app will behave exactly the same as the iOS app.

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[PRESIDENT810]

(I just signed CLA

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[facebook-github-bot]

@zeyap has imported this pull request. If you are a Meta employee, you can view this in D80821903.

[react-native-bot]

This pull request was successfully merged by Kaining Zhong in a03780d

^{When will my fix make it into a release? | How to file a pick request?}

[facebook-github-bot]

@zeyap merged this pull request in a03780d.

[mukti107]

this causes the issue, now changing the app language from englist to arabic still forces LTR instead of RTL.

Locale.getAvailableLocales()[0]
This gets the first locale in the list of ALL available locales installed on the device, not the current/preferred language. This is incorrect.

It should be using one of these instead:
Locale.getDefault() – the system's default locale
context.resources.configuration.locales[0] – the app's current locale (respects per-app language on Android 13+)

[PRESIDENT810]

@mukti107 I'm terribly sorry. I made a new PR #54986 and changed to your proposed method to decide the directionality. Please take a look and confirm if that fix your issue. Thanks a lot!