Update Emerge tools integration to use latest best practices

[rbro112]

Summary

Updates Emerge Tools integration to use best practices. Emerge has deprecated the GitHub action for Android in favor of the Gradle plugin.

I was also curious about incorporating Emerge snapshot testing. See emerge-android #2 for an example of that - happy to add that as well if Stripe is interested in trying Emerge's snapshot testing.

Motivation

We're doing this as Stripe recently reached out about an issue with their existing integration. We noticed a few old practices being used, so we figured we'd help update everything to the latest and greatest 😄 .

Testing

• [ ] Added tests
• [x] Modified tests
• [x] Manually verified

Screenshots

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Changelog

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