Deprecate widget flag: GTK_WIDGET_IS_SENSITIVE

Use gtk_widget_is_sensitive() instead

https://bugzilla.gnome.org/show_bug.cgi?id=69872

gtk/gtkexpander.c

@@ -955,7 +955,7 @@ static void
 gtk_expander_state_changed (GtkWidget    *widget,
 			    GtkStateType  previous_state)
 {
-  if (!GTK_WIDGET_IS_SENSITIVE (widget))
+  if (!gtk_widget_is_sensitive (widget))
     GTK_EXPANDER (widget)->priv->button_down = FALSE;
 }