Revert "Don't show email link if the user cannot be emailed."
Reason for revert: UserRightsProxy lacks canReceiveEmail
method, and thus Special:GlobalUserRights fails
This reverts commit a6ad9a3b231b6ca48c7cdebfa1adbe5122cb5a76.
Bug: T254417
Bug: T251534
Change-Id: Ic0f9fbb8eff18fedffd22cf3faffebccface753a