shell: Move type setup to class_init

Doing it on the class level is enough. The shell is a singleton
so this doesn't change anything in practice.
Signed-off-by: Guido Günther <guido.gunther@puri.sm>

src/shell.c

@@ -632,7 +632,6 @@ phosh_shell_constructed (GObject *object)
   gtk_icon_theme_add_resource_path (gtk_icon_theme_get_default (),
                                     "/sm/puri/phosh/icons");
   css_setup (self);
-  type_setup ();
 
   priv->lockscreen_manager = phosh_lockscreen_manager_new ();
   g_object_bind_property (priv->lockscreen_manager, "locked",
@@ -674,6 +673,8 @@ phosh_shell_class_init (PhoshShellClass *klass)
   object_class->set_property = phosh_shell_set_property;
   object_class->get_property = phosh_shell_get_property;
 
+  type_setup ();
+
   props[PHOSH_SHELL_PROP_TRANSFORM] =
     g_param_spec_enum ("transform",
                        "Transform",