Sanitize RemoteEmail user prop (#27170)

* Sanitize RemoteEmail user prop

If the server is configured to hide user emails, the "RemoteEmail"
user property will be sanitized as well, effectively hiding the real
email of remote users.

* fix merge conflict

---------

Co-authored-by: Doug Lauder <wiggin77@warpmail.net>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/model/user.go

@@ -637,6 +637,7 @@ func (u *User) Sanitize(options map[string]bool) {
 
 	if len(options) != 0 && !options["email"] {
 		u.Email = ""
+		delete(u.Props, UserPropsKeyRemoteEmail)
 	}
 	if len(options) != 0 && !options["fullname"] {
 		u.FirstName = ""