xsettings: Always fallback to ibus
Traditionally, we've used ibus strictly when necessary (i.e. there was an IM configured that required IBus to be enabled). A bit more recently, we added OSK checks so that environments with an OSK would also have IBus enabled so that GNOME Shell could track focus positions without pulling a11y.
Nowadays, we simply want ibus always enabled, even if the underlying keymap wouldn't seemingly use its features. We anyways want it for the handling of emojis and dead keys.
Always enable IBus for X11 clients, unless there is another IM configured in the global GSetting.
Closes: #705 (closed)