MM-11521/MM-11522 Fix being able to create users with invalid emails through API (#9199)

* MM-11522 Fix being able to create users with invalid emails through API

* Ensure store tests are using valid emails

* Add missing license header

* Remove invalid test case

* Fix TestUpdateOAuthUserAttrs

model/user.go

@@ -132,7 +132,7 @@ func (u *User) IsValid() *AppError {
 		return InvalidUserError("username", u.Id)
 	}
 
-	if len(u.Email) > USER_EMAIL_MAX_LENGTH || len(u.Email) == 0 {
+	if len(u.Email) > USER_EMAIL_MAX_LENGTH || len(u.Email) == 0 || !IsValidEmail(u.Email) {
 		return InvalidUserError("email", u.Id)
 	}