Font names with underscores incorrectly throw an error on Android in PaymentSheet

[goguda]

Describe the bug

When trying to use a font name with an underscore on Android in the appearance parameter for PaymentSheet, an error is incorrectly resolved:

Encountered an error when setting a custom font: appearance.font.family should only contain lowercase alphanumeric characters on Android, but received 'crimsonpro_bold'. This value must match the filename in android/app/src/main/res/font.

This is not accurate as Android font names may have underscores in them as well, in addition to lowercase alphanumeric characters.

To Reproduce

Steps to reproduce the behavior:

1. Put an underscore in the name of any custom font in android/app/src/main/res/font (ex. crimsonpro_regular.ttf)
2. Specify the font name with underscore when initializing PaymentSheet

Expected behavior

Font names with underscores should be accepted as well on Android, in addition to lowercase alphanumeric characters.

Smartphone (please complete the following information):

• Device: Android Emulator (API 34)
• OS: Android 14
• Browser: Stock browser

Additional context

I've already tested simply bypassing the if statement that checks for this and the font displays on the PaymentSheet correctly.

The fix will simply involve changing the regex expression in android/src/main/java/com/reactnativestripesdk/PaymentSheetAppearance.kt to allow for underscores. I will create a PR soon

[goguda]

PR #1637