Add slashes to regex string so emails can pass validation on register page

[srpiatt]

validatorjs schema regex fields need slashes before and after the regex, or else it returns a validation error. This blocks users from registering.

Checklist:

• Have you successfully tested with your changes locally?
• Have you successfully deployed to an AWS account with your changes?

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[srpiatt]

Reviewed in office hours, December 21, 2023.