Bump version to 2.31.0-beta.12

- Update app versionName for the beta 12 release
- Prepare the v2.31.0 branch for the GitHub prerelease and Play internal rollout

🤖 Auto-generated

Author: OwenMcGirr

app/build.gradle.kts

@@ -20,7 +20,7 @@ android {
         minSdk = 29
         targetSdk = 36
         versionCode = gitVersionCode()
-        versionName = "2.31.0-beta.11"
+        versionName = "2.31.0-beta.12"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables {