Incorrect file format uploads on spreadsheet causes a 500 #389
Description
Desktop
On desktop it does not allow you to upload an incorrect file which is fine however you can drag and drop one into the area instead of actually choosing to upload one and this causes a 500 error.
Mobile
Allows user to upload any file format and causes a 500 error.
Reproduce
Just drag a different file format other then what is recommended under the guidance for uploading
Screenshot
