Fix race condition in VerifyEmail with captcha

[FelixMalfait]

There's a race condition in VerifyEmail and in most cases the request being thrown from the useEffect (on component mount) is thrown before we have received the captcha. We should fix it and wait for the captcha to be available before throwing the request (if captcha is enabled in the app).

[FelixMalfait]

@AMoreaux tried to fix it but it was difficult so we removed the CaptchaGuard entirely