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 also was curious about incorporating Emerge snapshot testing. See #2 for an example of that.

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 out and update everything to the latest and greatest 😄 .

Testing

• Added tests
• Modified tests (see status checks)
• Manually verified

Screenshots

N/A

Changelog

N/A

[github-actions]

Risky Change

This is considered a risky change because it adjusts the sample app build.gradle, please review carefully.
We've seen issues in the past which resulted in failed builds for merchants. Please make sure the build.gradle change is intended.

By adding the label accept-risky-change to this PR, I acknowledge that I'm changing an example app and have verified that the SDK remains in a shippable state.

[github-actions]

Diffuse output:

OLD: identity-example-release-base.apk (signature: V1, V2)
NEW: identity-example-release-pr.apk (signature: V1, V2)

          │            compressed            │           uncompressed           
          ├─────────────┬─────────────┬──────┼─────────────┬─────────────┬──────
 APK      │ old         │ new         │ diff │ old         │ new         │ diff 
──────────┼─────────────┼─────────────┼──────┼─────────────┼─────────────┼──────
      dex │       2 MiB │       2 MiB │  0 B │     4.2 MiB │     4.2 MiB │  0 B 
     arsc │ 1,023.9 KiB │ 1,023.9 KiB │  0 B │ 1,023.8 KiB │ 1,023.8 KiB │  0 B 
 manifest │     2.3 KiB │     2.3 KiB │  0 B │       8 KiB │       8 KiB │  0 B 
      res │   301.5 KiB │   301.5 KiB │  0 B │     455 KiB │     455 KiB │  0 B 
   native │     6.2 MiB │     6.2 MiB │  0 B │    15.8 MiB │    15.8 MiB │  0 B 
    asset │     6.7 KiB │     6.7 KiB │  0 B │     6.5 KiB │     6.5 KiB │  0 B 
    other │    85.5 KiB │    85.5 KiB │ +5 B │   158.7 KiB │   158.7 KiB │  0 B 
──────────┼─────────────┼─────────────┼──────┼─────────────┼─────────────┼──────
    total │     9.6 MiB │     9.6 MiB │ +5 B │    21.6 MiB │    21.6 MiB │  0 B 

 DEX     │ old   │ new   │ diff      
─────────┼───────┼───────┼───────────
   files │     1 │     1 │ 0         
 strings │ 21305 │ 21305 │ 0 (+0 -0) 
   types │  6770 │  6770 │ 0 (+0 -0) 
 classes │  5559 │  5559 │ 0 (+0 -0) 
 methods │ 31123 │ 31123 │ 0 (+0 -0) 
  fields │ 18141 │ 18141 │ 0 (+0 -0) 

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  164 │  164 │  0   
 entries │ 3392 │ 3392 │  0

APK

   compressed    │  uncompressed   │                                           
──────────┬──────┼──────────┬──────┤                                           
 size     │ diff │ size     │ diff │ path                                      
──────────┼──────┼──────────┼──────┼───────────────────────────────────────────
 28.3 KiB │ +4 B │ 62.6 KiB │  0 B │ ∆ META-INF/CERT.SF                        
    272 B │ +1 B │    120 B │  0 B │ ∆ META-INF/version-control-info.textproto 
──────────┼──────┼──────────┼──────┼───────────────────────────────────────────
 28.6 KiB │ +5 B │ 62.7 KiB │  0 B │ (total)