Description

When attempting to upload custom fonts, the upload functionality works as expected for font files. However, when a ZIP file (or potentially other non-font file formats) is uploaded by mistake, the UI shows an infinite loading state, instead of an error message.

Step-by-step reproduction instructions

• Go to the Font Library modal and select the Upload tab
• Upload a zip by a drag & drop
• See the infinite loading state

Screenshots, screen recording, code snippet

Environment info

Gutenberg >= 17.6

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

No