What does this PR do?

This PR prevents the email input on the signup page if a new user is invited to a team. This is to prevent any bugs in the future.

New user

Normal signup page

Fixes # (issue)

Environment: Staging(main branch) / Production

Type of change

• Bug fix (non-breaking change which fixes an issue)

How should this be tested?

• Invite a new user to a team
• When accepting the invite the email input should be disabled
• Visit CAL_URL/signup
  • You should be able to input an email

Checklist

• I haven't read the contributing guide
• My code doesn't follow the style guidelines of this project
• I haven't performed a self-review of my own code and corrected any misspellings
• I haven't commented my code, particularly in hard-to-understand areas
• I haven't checked if my PR needs changes to the documentation
• I haven't checked if my changes generate no new warnings
• I haven't added tests that prove my fix is effective or that my feature works
• I haven't checked if new and existing unit tests pass locally with my changes