As our UX, Carrie, pointed out in https://bugzilla.mozilla.org/show_bug.cgi?id=914454#c87, we would keep the current behavior, which is  to show "el+sms" layout when in Message app, and would not allow the user to switch to the normal Greek layout.

And I will just disable the auto correction for "el+sms" case, unless we have a simple way to enable this.
This is to minimize the scope of this change.

Thanks.