Remove sleep() from hydroponics.dm (tgstation#57344)

remove sleep() from a couple of hydroponic procs, use addtimer and callbacks instead, closes tgstation#56435

code/modules/hydroponics/hydroponics.dm

@@ -434,10 +434,8 @@
 	harvest = FALSE
 	weedlevel = 0 // Reset
 
-	sleep(5) // Wait a while
-	update_appearance()
-	visible_message("<span class='warning'>[oldPlantName] suddenly mutates into [myseed.plantname]!</span>")
-	TRAY_NAME_UPDATE
+	var/message = "<span class='warning'>[oldPlantName] suddenly mutates into [myseed.plantname]!</span>"
+	addtimer(CALLBACK(src, .proc/after_mutation, message), 0.5 SECONDS)
 
 /obj/machinery/hydroponics/proc/mutateweed() // If the weeds gets the mutagent instead. Mind you, this pretty much destroys the old plant
 	if( weedlevel > 5 )
@@ -454,13 +452,17 @@
 		harvest = FALSE
 		weedlevel = 0 // Reset
 
-		sleep(5) // Wait a while
-		update_appearance()
-		visible_message("<span class='warning'>The mutated weeds in [src] spawn some [myseed.plantname]!</span>")
-		TRAY_NAME_UPDATE
+		var/message = "<span class='warning'>The mutated weeds in [src] spawn some [myseed.plantname]!</span>"
+		addtimer(CALLBACK(src, .proc/after_mutation, message), 0.5 SECONDS)
 	else
 		to_chat(usr, "<span class='warning'>The few weeds in [src] seem to react, but only for a moment...</span>")
-
+/**
+ * Called after plant mutation, update the appearance of the tray content and send a visible_message()
+ */
+/obj/machinery/hydroponics/proc/after_mutation(message)
+		update_appearance()
+		visible_message(message)
+		TRAY_NAME_UPDATE
 /**
  * Plant Death Proc.
  * Cleans up various stats for the plant upon death, including pests, harvestability, and plant health.