Add link to support on phone verification

[gtsiolis]

Description

Following up from #12258, this will duplicate the link to support on the phone verification step when users are entering the mobile phone number, not just the verification code. The reasons behind this change:

1. We've gotten some from users in China that they are not able to use this feature using their mobile phone number. We're actively working on resolving this with the third-party service we're integrating for this feature, Twilio. See relevant discussion (internal). Cc @svenefftinge @securitymirco @KlasenK
2. Future errors like this that prevent users from entering a mobile phone number will still end up in the same verification step, which currently doesn't include the link to support as in the next step, which is for entering the verification code.

How to test

1. Create a new GitHub account and sign in to the preview environment.
2. Remember to unblock the user in /admin/users. 🎗️
3. Try opening a new workspace and noticed you'll be prompted to go through the phone verification process.
4. Notice there's a link to support when entering a mobile phone number.

Release Notes

Add link to support on phone verification

Werft options:

• /werft with-preview

[gtsiolis]

Danke, @svenefftinge! 🍦