Use legacy JNI packaging for ARM64 Android E2E APKs

[cortinico]

Summary:

Follow-up to #58092.

Android API 35 x86_64 emulator images expose both x86_64 and arm64-v8a through libndk_translation.so. SoLoader 0.12.1 only searches the first ABI when loading uncompressed native libraries directly from the APK, causing ARM64-only RNTester and template apps to crash while loading libreactnative.so.

Enable legacy JNI packaging through a CI-only Gradle init script so Android extracts the ARM64 libraries and the existing SoLoader ApplicationSoSource can load them. This applies only to dry-run RNTester builds and Android template E2E builds. Nightly and release packaging is unchanged.

Failure evidence: https://github.com/react/react-native/actions/runs/32741094253

Changelog:

[INTERNAL] [FIXED] - Extract native libraries for ARM64 Android E2E APKs running through NDK translation.

Test Plan:

• ./node_modules/.bin/prettier --check .github/actions/build-android/action.yml .github/workflows/e2e-android-templateapp.yml — passed.
• Parsed both modified YAML files with the yaml Node package — passed.
• Parsed the embedded workflow shell scripts with bash -n — passed.
• Compiled .github/workflow-scripts/legacy-jni-packaging.gradle with the Groovy compiler bundled with Gradle 9.4.1 — passed.
• Full Android E2E validation is delegated to this draft PR because the local Gradle daemon could not establish its localhost connection.

[meta-codesync]

@cortinico has imported this pull request. If you are a Meta employee, you can view this in D117222109.

[meta-codesync]

@cortinico merged this pull request in 4f9f24e.