fix: set cardbrand tint color for CardField

[charliecruzan-stripe]

Summary

The CardBrandView tint color is only set to cardNumberEditText.hintTextColor on initialization. Since we're setting that tintColor after initializing, it doesn't trickle down to the cardbrandview. Also, CardBrandView.tintColorInt is internal, so we have to use reflection to set it. If that fails (i.e. the field name changes or something like that) we just log it and move on without crashing the app.

also simplified cardInputWidgetBinding declarations down to just one

Motivation

closes #459, + achieve parity with iOS

Testing

• I tested this manually
• I added automated tests

Documentation

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