This was originally tracked in #16506.
Support was added in #16511.
But turns out people didn't expect the Terminal to actually be like, compliant: #16654

So now we're gonna add a setting to be able to manually enable/disable support for toggling this mode.

The trick here? ConPTY is the thing that's going to need to do the input translation, not the Terminal. So, the Terminal needs a way to tell conpty (at runtime)¹ if this is a mode that's allowed or not. And that, we don't have a good system set up for currently.