Make UploadNativeSymbolsTask work on the root project level

[romtsn]

Description

Currently UploadNativeSymbolsTask is registered only for the app module, but it should be registered on the root project level, and since it invokes the sentry-cli, it will recursively scan all subfolders for native debug symbols.

The challenge will be with how to automatically hook it with the release tasks (since those are registered on the app module level). Perhaps we could have a dummy task registered on the app module level that calls to the root project task, not sure yet.