st/entry: Only handle primary/secondary icon clicks when reactive

Just like the internal ClutterText, the icon actors are part of the
entry. It therefore makes sense for the icons to not react to clicks
when the entry itself is non-reactive; again, just like the text.

That behavior is also consistent with icons in GTK entries.

https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3138

src/st/st-entry.c

@@ -1312,6 +1312,9 @@ _st_entry_icon_clicked_cb (ClutterClickAction *action,
 {
   StEntryPrivate *priv = ST_ENTRY_PRIV (entry);
 
+  if (!clutter_actor_get_reactive (CLUTTER_ACTOR (entry)))
+    return;
+
   if (actor == priv->primary_icon)
     g_signal_emit (entry, entry_signals[PRIMARY_ICON_CLICKED], 0);
   else