Since GTK 4.8, gtk_widget_dispose_template() is available to
automatically unparent child widgets from templated GtkWidgets. This is
only needed for GtkWidget derived classes, as most other classes will
automatically unparent their children.
This makes widget implementations slightly simpler, and is also
recommended at
https://developer.gnome.org/documentation/tutorials/widget-templates.html
So, start using that function where we can.
This was a copy-pasta mistake when creating the CcListRowInfoButton
class from the CcListRow class.
The mistake was harmless but fixing it is good for the sake of
consistency and to avoid confusion in backtraces.
