No form validation feedback on Firefox Mobile

[mwild1]

This is ultimately a Firefox bug (#1510450) but it results in no feedback being given to users when we depend on local form validation.

For example, in the manual web registration form, if the user enters a password that is too short, the browser will not allow the form to submit, but it fails to notify the user. It works fine on other browsers, and it looks like the Firefox developers do intend to address the issue. However the issue has been open for 6 years, so a fix may not be right around the corner.

If we want to fix this ourselves, we could attempt some CSS or JS to show an error to the user instead, or remove local validation entirely (probably leading to a worse user experience overall) and do the validation on the server side instead.