Improve error messaging when uploading image via URL

[dboyer]

Two issues with error messages when trying to upload images via URL.

• [ ] I tried to upload a profile photo while logged in as a student and could not upload a gif but also didn't receive any error message telling me it was an incorrect file type. I just kept clicking the button to upload and nothing happened.
• [ ] I logged in as a chapter ambassador and tried to upload a gif via URL as a team photo, it briefly flashed the error message below but it was hard to understand as the message went away quickly.

[viviancan]

Hi Deb! I will investigate further. I am not sure how custom the error messages can be with filestack. The current error messages displayed are the default message/styling provided by filestack.

[dboyer]

Thanks @viviancan ! This is definitely a nice to have so don't worry about digging too deeply. Thanks for looking!