Machine var shim (#18644)

* removal of machine var

* shimsham

* deprecation warnings

* COMSIG_LIVING_HANDLE_VISION signal

* improved

* more cleanup

* more fixes

* this is fine

* fixed radios

* notices for now, tgui fix

* cleaned up hud and vision parent calls, adds COMSIG_LIVING_HANDLE_HUD

* radios use tgui now

* guestpass does not need machine anymore

* cloning machine doesn't use it

* this arcade machine is tgui too

* autolathe does not need machine

* remaining cleanup

* doc fix

* fix

* logout handling

---------

Co-authored-by: Cameron Lennox <killer65311@gmail.com>

code/controllers/subsystems/tgui.dm

@@ -130,8 +130,6 @@ SUBSYSTEM_DEF(tgui)
 	for(var/datum/tgui/ui in user.tgui_open_uis)
 		if(ui.window && ui.window.id == window_id)
 			ui.close(can_be_suspended = FALSE)
-	// Unset machine just to be sure.
-	user.unset_machine()
 	// Close window directly just to be sure.
 	user << browse(null, "window=[window_id]")