Changed the email validation for only encoded chars

What does this MR do and why?

The fix for email validation was done through a security fix - https://gitlab.com/gitlab-org/gitlab/-/issues/441093 and was back-ported to release 16-11, 16-10, 16-9.

Hence now a bug-fix for issue that occured due to the respective change #458764 (closed) - will need to be back-ported too.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• The MR that fixed the bug on the default branch has been deployed to GitLab.com (not applicable for documentation or spec changes).
• This MR has a severity label assigned (if applicable).
• Set the milestone of the merge request to match the target backport branch version.
• This MR has been approved by a maintainer (only one approval is required).
• Ensure the e2e:package-and-test-ee job has either succeeded or been approved by a Software Engineer in Test.

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