Assert unique email addresses (PHP UserCommands)

Created utility UserCommands::assertUniqueIdentity() to verify unique updated username and email address for the following:
createUser, register, sendInvite, updateUser

UserCommands::updateUserProfile changed to not update username or email address.

Changed User Profile UI to not allow email to be changed.
Also updated API_CRUD_Test to make users with unique identity
userProfile E2E updated to not modify email address