createSignedUploadUrl does not validate mime type.

[saqibameen]

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

If I create a signed upload url using createSignedUploadUrl and upload a file with a different mime type, it does not stop.

E.g.,
1- create signedUploadUrl for file.md
2- upload test.pdf buffer with Content-Type: application/pdf in headers
✅ Successfully uploaded

1- create signedUploadUrl for file.md
2- upload test.pdf buffer with Content-Type: text/markdown in headers
✅ Successfully uploaded

To Reproduce

Do following on the above two test cases:

1. create SignedUploadUrl
2. Upload file

Expected behavior

It should give error that mime type does not match.

Screenshots

NA

System information

• OS: macOS
• Version of supabase-js: 2.44.4
• Version of Node.js: NA (using cloudflare worker)