google_firebase_android_app should be replaced when package_name changes

[modular-magician]

This is already the behavior in the API. It was forgotten in the initial PR. However, it's not a common operation for an app to change the package_name mid-way, so it probably has little real impact.

Release Note Template for Downstream PRs (will be copied)

firebase: made the `google_firebase_android_app` resource's `package_name` field required and immutable. This prevents API errors encountered by users who attempted to update or leave that field unset in their configurations.

Derived from GoogleCloudPlatform/magic-modules#10194

[github-actions]

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