Can't use `user_metadata` in RLS policies when uploading a file

[miwelc]

Bug report

• I confirm this is a bug with Supabase, not with my own application.
• I confirm I have searched the Docs, GitHub Discussions, and Discord.

Describe the bug

I can't use custom values in user_metadata in RLS policies because they are not available in that context.
From what I've read it's because storage.can_insert_object(...) is not being called with user_metadata and so it doesn't fake insert that info.

To Reproduce

Create a RLS policy that just checks any value in user_metadata.

Expected behavior

I can access in the RLS policy the custom values I defined during the upload call.

System information

• OS: macOs
• Browser (if applies):
• Version of supabase-js: 2.56.0
• Version of Node.js: 22.12