clutter: Reset ClutterInputFocus on focus_out

Focus changes should trigger an IM reset, as some engines do want
to maybe commit the preedit buffer before changing focus. Since
the preedit string is also cleared on reset(), we can do without
that explicit call.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2384>

clutter/clutter/clutter-text.c

@@ -3193,7 +3193,7 @@ clutter_text_key_focus_out (ClutterActor *actor)
 
   if (priv->editable && clutter_input_focus_is_focused (priv->input_focus))
     {
-      clutter_text_set_preedit_string (CLUTTER_TEXT (actor), NULL, NULL, 0);
+      clutter_input_focus_reset (priv->input_focus);
       clutter_input_method_focus_out (method);
     }