Give admins the ability to put a popup notice for players in tickets (#61010)

Admins can now give players a popup if they are not responding to tickets.
Popup is cleared when player replies or ticket is resolved/closed.
As more and more of the chat screen is made irrelevant, new players read it less and less.
This means that a lot of new players are ignoring ahelps, which is something I've encountered myself.

code/modules/admin/topic.dm

@@ -1055,6 +1055,22 @@
 		to_chat(H, span_adminnotice("Your prayers have been answered!! You received the <b>best [new_item.name]!</b>"), confidential = TRUE)
 		SEND_SOUND(H, sound('sound/effects/pray_chaplain.ogg'))
 
+	else if (href_list["adminpopup"])
+		if (!check_rights(R_ADMIN))
+			return
+
+		var/message = input(owner, "As well as a popup, they'll also be sent a message to reply to. What do you want that to be?", "Message") as text|null
+		if (!message)
+			to_chat(owner, span_notice("Popup cancelled."))
+			return
+
+		var/client/target = locate(href_list["adminpopup"])
+		if (!istype(target))
+			to_chat(owner, span_notice("The mob doesn't exist anymore!"))
+			return
+
+		give_admin_popup(target, owner, message)
+
 	else if(href_list["adminsmite"])
 		if(!check_rights(R_ADMIN|R_FUN))
 			return