events: Add explicit break

This doesn't particularly matter, since we fall through into a default
case that does nothing right below, but this matches the other paths
and it prevents us from falling into a trap if we add other event types
below.

src/core/events.c

@@ -2146,6 +2146,7 @@ meta_display_handle_event (MetaDisplay        *display,
           bypass_clutter = TRUE;
           bypass_wayland = TRUE;
         }
+      break;
 
     default:
       break;