Use available runner for Android build

Author: cipolleschi

.github/workflows/test-all.yml

@@ -288,7 +288,7 @@ jobs:
           gradle-cache-encryption-key: ${{ secrets.GRADLE_CACHE_ENCRYPTION_KEY }}
 
   build_android:
-    runs-on: 8-core-ubuntu
+    runs-on: ubuntu-latest
     needs: [set_release_type]
     container:
       image: reactnativecommunity/react-native-android:v20.0