build: upgrade AGP to 9.0.0 and Gradle to 9.2.1

Upgrades the Android Gradle Plugin to 9.0.0, the Gradle Wrapper to 9.2.1, and the Compose Screenshot plugin to 0.0.1-alpha13. This resolves configuration issues with the 'GenerateTestConfig' task where 'mergedManifest' was not properly configured.

Also:
- Adopts AGP 9.0 compatibility flags in gradle.properties.
- Removes obsolete 'testDebugScreenshotTest' and 'testReleaseScreenshotTest' exclusions from CI workflows.

Author: dkhawk

.github/workflows/test.yml

@@ -42,7 +42,7 @@ jobs:
         distribution: 'temurin'
 
     - name: Build modules
-      run: ./gradlew build jacocoTestReport -x :maps-app:generateDebugScreenshotTestConfig -x :maps-app:testDebugScreenshotTest -x :maps-app:generateReleaseScreenshotTestConfig -x :maps-app:testReleaseScreenshotTest --stacktrace
+      run: ./gradlew build jacocoTestReport -x :maps-app:generateDebugScreenshotTestConfig -x :maps-app:generateReleaseScreenshotTestConfig --stacktrace
 
     - name: Run Screenshot Tests
       run: ./gradlew :maps-app:validateDebugScreenshotTest