Cleans up a use of air_contents in pipeline code, it's not doing anything yet, but if someone wants to change how reactions work they might break it. Adds a proc override to catch taking damage, which fixes the canister not leaking until it's updated (#58829)

code/modules/atmospherics/machinery/datum_pipeline.dm

@@ -240,7 +240,7 @@
 			else if (istype(atmosmch, /obj/machinery/atmospherics/components/unary/portables_connector))
 				var/obj/machinery/atmospherics/components/unary/portables_connector/considered_connector = atmosmch
 				if(considered_connector.connected_device)
-					gas_mixture_list += considered_connector.connected_device.air_contents
+					gas_mixture_list += considered_connector.connected_device.return_air()
 
 	var/total_thermal_energy = 0
 	var/total_heat_capacity = 0

code/modules/atmospherics/machinery/portable/canister.dm

@@ -500,6 +500,12 @@ GLOBAL_LIST_INIT(gas_id_to_canister, init_gas_id_to_canister())
 		to_chat(user, "<span class='notice'>You repair some of the cracks in [src]...</span>")
 	return TRUE
 
+/obj/machinery/portable_atmospherics/canister/take_damage(damage_amount, damage_type = BRUTE, damage_flag = "", sound_effect = TRUE, attack_dir, armour_penetration = 0)
+	. = ..()
+	if(!.)
+		return
+	SSair.start_processing_machine(src)
+
 /obj/machinery/portable_atmospherics/canister/obj_break(damage_flag)
 	. = ..()
 	if(!.)