"Upload profile" has hanged and failed to upload several times recently

I can't reliably reproduce this but it has happened to me ~3 times recently (past week or so).

### STR
In a profile:

* Click "Upload profile"
* CLick "Submit"

### Expected
Profile uploads

### Actual
The progress bar moves across the screen to the end and stops. Eventually, the profile fails to upload and I can re-click the "Upload profile" button to try again.

If I wait long enough after the failure and try again (maybe 5min?), the upload is successful.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-432)