Change email address workflow is broken, results in empty JSON string being shown in browser

Describe the bug If an authenticated Common Voice user tries to change their email address from the page at https://commonvoice.mozilla.org/en/profile/settings they are redirected via SSO to https://auth.mozilla.auth0.com/login? This interface is intuitive, and they need to enter the new email address in the login box. related: #2110 for UI awkwardness

If they persist, and enter a new email address, a confirmation email is sent to the new email address. Clicking on the confirmation email results in the following being shown in the browser window:

{

    "message": ""

}

Expected behavior Easily able to change email address of account

Screenshots If applicable, add screenshots to help explain your problem.

Desktop or Mobile (please complete the following information):

• first reported on Windows 10 64 bit Firefox desktop
• validated by Kathy Reid on Linux Ubuntu 20.04 LT on Firefox 87

Additional Hardware (were you using headphones, an external speaker or an external microphone?): Not relevant to use case

Additional context This was reported via the CommonVoice email inbox, details of reporter not included to protect privacy.

[phirework]

Yeah, let’s try to have them re-test. The auth system is largely out of my control unfortunately as it’s integrated with Mozilla IAM, and I haven’t made any changes to the client code in a while, so it could’ve been a big on the SSO side that has since been fixed.

[phirework]

It is honestly rude that GH doesn’t allow 😭 as a reaction. Will investigate, thanks!