CMS User creation/E-mail address containing apostrophe fails to validate

The issue:
In CMS admin perspective, user profile cannot be created when an e-mail address contains apostrophe before @ (ex, o'brian@email.com) which is permitted by some e-mail service providers. The e-mail validation fails.

To reproduce

1. Open CMS console
2. Click on Users
3. Click link "Create User"
4. Enter an e-mail address with an apostrophe (ex. o'brian@e-mail.com)
5. Enter other values and save.

Solution recommendation:
Is it possible to have the e-mail validation regex saved as a CMS configuration and allow that regex to be modified optionally as desired by the specific implementation? .. and utilize the regex if available in CMS configuration for validating e-mail addresses.