feat: add dark google pay button option

[charliecruzan-stripe]

Summary

Added support for pay_dark and standard_dark to the <GooglePayButton /> component's type prop. This allows you to display the dark Google Pay button.

This includes a breaking change.
This changes the <GooglePayButton /> component behavior in that it no longer automatically uses the dark version when the device is in Dark Mode. Instead, merchants should detect Dark Mode in their app (part of react native core) and use the <GooglePayButton /> type prop appropriately (according to Google's guidelines).

This PR doesn't add any additional assets, it just moves assets from the *-night directories into the main drawable directories. Previously, the dark google pay buttons were only shown if the device was in dark mode. (see breaking change)
Actually- this PR removes some unused assets 😄

Motivation

requested by users, Google will sometimes reject an app if the app isn't using the dark button when on a light background

Testing

• I tested this manually
• I added automated tests

Screen.Recording.2022-07-20.at.3.10.26.PM.mov

Documentation

Select one:

• I have added relevant documentation for my changes. (API Ref)
• This PR does not result in any developer-facing changes.