Converts AI controller processing subsystems to use currentrun (#94905)

## About The Pull Request

this makes it so `SSai_controllers` and its subtypes use a `currentrun`
loop, instead of directly looping thru
`GLOB.ai_controllers_by_status[planning_status]`

## Why It's Good For The Game

most other processing subsystems do this, why shouldn't we?
it should ensure all ai controllers get to process, even if the server's
under load.

## Changelog

no player-facing changes, prolly

code/datums/ai/_ai_controller.dm

@@ -84,6 +84,10 @@ multiple modular subtrees with behaviors
 	UnpossessPawn(FALSE)
 	if(ai_status)
 		GLOB.ai_controllers_by_status[ai_status] -= src
+		for(var/datum/controller/subsystem/ai_controllers/controller_subsystem in Master.subsystems)
+			if(controller_subsystem.planning_status == ai_status)
+				controller_subsystem.currentrun -= src
+				break
 	our_cells = null
 	set_movement_target(type, null)
 	if(ai_movement.moving_controllers[src])
@@ -431,6 +435,10 @@ multiple modular subtrees with behaviors
 	//remove old status, if we've got one
 	if(ai_status)
 		GLOB.ai_controllers_by_status[ai_status] -= src
+		for(var/datum/controller/subsystem/ai_controllers/controller_subsystem in Master.subsystems)
+			if(controller_subsystem.planning_status == ai_status)
+				controller_subsystem.currentrun -= src
+				break
 	remove_from_unplanned_controllers()
 	stop_previous_processing()
 	ai_status = new_ai_status