Misc disposal fixes (#22666)

Stickers can no longer be attached to disposal machinery or conveyors,
to prevent further issues with throwing them there.
The disposal outlet sprite was set to face the wrong direction when
expelling items, for two of its directions. This was fixed.
The disposal UI constantly reopening itself was fixed.
And a set of disposal systems were added to runtime for easier
debugging.
<img width="344" height="385" alt="image"
src="https://github.com/user-attachments/assets/ff93f3e9-bfa7-480c-9d6b-c501b02ca51a"
/>

code/modules/recycling/conveyor2.dm

@@ -195,6 +195,9 @@
 	..()
 	update()
 
+/obj/structure/machinery/conveyor/can_attach_sticker(mob/user, obj/item/sticker/S)
+	return FALSE
+
 // the conveyor control switch
 //
 //

code/modules/recycling/disposal.dm

@@ -497,7 +497,7 @@
 				feedback_inc("disposal_auto_flush",1)
 				flush()
 		flush_count = 0
-	src.updateDialog()
+	SStgui.update_uis(src)
 
 	// If we're ready, don't draw any extra power
 	if(mode == MODE_READY || !uses_air)
@@ -654,6 +654,8 @@
 	else
 		return ..()
 
+/obj/structure/machinery/disposal/can_attach_sticker(mob/user, obj/item/sticker/S)
+	return FALSE
 
 /**
  * Virtual disposal object