fix: The Shorebird Updater is unavailable in the current environment.

[FlyMoew]

App ID: 2676b363-e494-49aa-837d-98d944f96b45

Description

When updating the patch package through the [shorebird_downloader] plugin, it prompts that the current environment cannot be updated. Even after setting up the proxy, it still cannot be updated normally. Has the new version imposed restrictions on the network and region? Please confirm and inform us of the reason. Thank you!

Steps To Reproduce

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected Behavior

I hope the patch can be downloaded normally

Screenshots

[eseidel]

This happens when the app was built with flutter build (or flutter run) rather than shorebird release.