Make sure AndroidDownloadManager is not used
From https://gitlab.torproject.org/tpo/applications/fenix/-/issues/34177#note_2707927.
In Fenix, only `FetchDownloadManager` seems to be used currently, but in `DownloadsFeature`, `AndroidDownloadManager` is used by default if `downloadManager` is not explicitly passed. We should double check this and maybe patch `AndroidDownloadManager` to make sure it cannot be used.
issue