Stop lower-casing email on user search

[helmus]

Per the documentation here:
https://auth0.com/docs/api/management/v2#!/Users_By_Email/get_users_by_email

If Auth0 is the identify provider (idP), the email address associated with a user is saved in lower case, regardless of how you initially provided it. For example, if you register a user as JohnSmith@example.com, Auth0 saves the user's email as johnsmith@example.com.

In cases where Auth0 is not the idP, the email is stored based on the rules of idP, so make sure the search is made using the correct capitalization.

[lbalmaceda]

Thanks!