Supabase Branching and Vercel Environments

# Bug report - [x] I confirm this is a bug with Supabase, not with my own application. - [x] I confirm I have searched the [Docs](https://docs.supabase.com), GitHub [Discussions](https://github.com/supabase/supabase/discussions), and [Discord](https://discord.supabase.com). ## Describe the bug Not being able to choose a custom created Vercel environment in the Vercel integration for synchronizing environment variables. ## Expected behavior Being able to choose the custom created Vercel environment in the Vercel integration for synchronizing environment variables. Additional information: I have a Git branch called _staging_ which is tied to a custom Vercel environment called _staging_ and therefore it would be a streamlined process if I could get it to synchronize the environment variables to that environment. ## Screenshots <img width="1218" height="994" alt="Image" src="https://github.com/user-attachments/assets/449389fd-ada5-476d-a1cf-b502b3740050" /> <img width="1210" height="513" alt="Image" src="https://github.com/user-attachments/assets/07f0dd15-519d-4e44-9eb1-822776c86c5c" />