Improving the message for users without permission to add attachments

Currently, when a user attempts to add an attachment to a page (by dragging and dropping the file), they encounter an HTTP error message if they haven't been granted the Add Attachments permission within that space.

It would be really helpful to enhance this error message by explaining why it's happening: because of a permission issue.

Ps: to confirm the issue is occurring because of a lack of permission, check if the "Add image, video or file"  button is available on the editor toolbar. If that button isn't there, the user didn't receive the Add Attachments permission.