Remove key handling from ContainerWidget

It has no business handling key input. This was used only for opening the ingame chat and replacing it with a `LogicKeyListener` was trivial.

OpenRA.Mods.Common/Widgets/Logic/Ingame/IngameChatLogic.cs

@@ -209,7 +209,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				var chatClose = chatChrome.Get<ButtonWidget>("CHAT_CLOSE");
 				chatClose.OnClick += CloseChat;
 
-				chatPanel.OnKeyPress = e =>
+				var openChatKeyListener = chatPanel.Get<LogicKeyListenerWidget>("OPEN_CHAT_KEY_LISTENER");
+
+				openChatKeyListener.AddHandler(e =>
 				{
 					if (e.Event == KeyInputEvent.Up)
 						return false;
@@ -223,7 +225,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					}
 
 					return false;
-				};
+				});
 			}
 
 			chatScrollPanel = chatChrome.Get<ScrollPanelWidget>("CHAT_SCROLLPANEL");