proguard-android.txt breaks builds on AGP 9 — switch to proguard-android-optimize.txt

[kinggolf]

Describe the bug
Using proguard-android.txt in android/build.gradle breaks builds on AGP 9

To Reproduce
Upgrade project to Android Plugin Gradle 9 - in android/build.grade:

classpath 'com.android.tools.build:gradle:9.1.1'

Then build Android project.

Expected behavior
Expect project to build and run normally.

Actual behavior

A problem occurred evaluating project ':app'.
> `getDefaultProguardFile('proguard-android.txt')` is no longer supported since it includes `-dontoptimize`, which prevents R8 from performing many optimizations. Instead use `getDefaultProguardFile('proguard-android-optimize.txt)`, and if needed, temporarily use `-dontoptimize` in a custom keep rule file while fixing breakages.

Additional context
See Android Docs

Fix in android/build.gradle

-            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'