It appears that FTU always lists English as the default language. So if I've got my language set to French, and then I do Settings->Device Information->More Information->Run FTU.  I see English as the default language. So I just click Next to switch to engish. That works for switching the language, but it looks like no change event ever happens and your new code here never gets called.  When I'm done with the FTU app, I still have all the otherlatins keyboards enabled.

I suggest that we just drop all the changes to the FTU app and only change the keyboard and settings app in this patch.  This is because:

1) I don't know anything about FTU and I'm very nervous about changing it list late.

2) Users will almost never run it more than once, so there will never be multiple keyboard groups selected when it is run (that is, your new code here will rarely ever make a difference)

3) It doesn't work in the "switch back to the default language" case anyway.