Failure expected when android_library has assets but no manifestattr defined

[nkoroste]

According to https://bazel.build/reference/be/android#android_binary.manifest:

The name of the Android manifest file, normally AndroidManifest.xml. Must be defined if resource_files or assets are defined.

The native android rules behave as expected however Starlark rules android will not fail if a manifest is missing but assets are present. See:

• Native https://github.com/bazelbuild/bazel/blob/master/src/main/java/com/google/devtools/build/lib/rules/android/AndroidResources.java#L89
• Starlark: https://github.com/bazelbuild/rules_android/blob/main/rules/resources.bzl#L1372

Bonus: we should also consider to introduce a new flag which if set will automatically create an empty manifest with the correct package rather than fail the build. This will closer match what Gradle does.