Fix: Crash if interface scale or font size changes with chat box present. (#12705)

Caused by the chat box being undrawn with the new dimensions, leading to out-of-bounding memory access.

src/window.cpp

@@ -3330,6 +3330,7 @@ void ReInitAllWindows(bool zoom_changed)
 		ReInitWindow(w, zoom_changed);
 	}
 
+	if (_networking) NetworkUndrawChatMessage();
 	NetworkReInitChatBoxSize();
 
 	/* Make sure essential parts of all windows are visible */