### Godot version

v4.1.1.stable.official [bd6af8e0e]

### System information

Godot v4.1.1.stable - Debian GNU/Linux trixie/sid trixie - Vulkan (Compatibility) - Mesa Intel(R) HD Graphics 520 (SKL GT2) () - Intel(R) Core(TM) i7-6500U CPU @ 2.50GHz (4 Threads)

### Issue description

After right clicking in thet "Filter Nodes" menu in the scene tree dock, the sub-menu is populated with a "Search" icon.

If I later switch themes in the same session, this icon is never updated to match the new theme.

![image](https://github.com/godotengine/godot/assets/660911/14336bb3-12ca-48c8-b030-8ada6ac27ec6)


### Steps to reproduce

1. Right click in the "Filter Nodes" menu in scene tree dock
2. Switch themes
3. Right click again in the "Filter Nodes" menu

Expected result: Icon has updated to match the theme I am currently using
Actual result: Icon is still using the theme I launched Godot with

### Minimal reproduction project

N/A
shader_create_dialog->disconnect("shader_created", callable_mp(this, &SceneTreeDock::_shader_created));
	shader_create_dialog->disconnect("confirmed", callable_mp(this, &SceneTreeDock::_shader_creation_closed));
	shader_create_dialog->disconnect("canceled", callable_mp(this, &SceneTreeDock::_shader_creation_closed));
}
void SceneTreeDock::_toggle_editable_children_from_selection() {
	List<Node *> selection = editor_selection->get_selected_node_list();
	List<Node *>::Element *e = selection.front();
	if (e) {
		_toggle_editable_children(e->get());
	}
}
void SceneTreeDock::_toggle_placeholder_from_selection() {
	List<Node *> selection = editor_selection->get_selected_node_list();
	List<Node *>::Element *e = selection.front();
	if (e) {
		Node *node = e->get();
		if (node) {
			_toggle_editable_children(node);
			bool placeholder = node->get_scene_instance_load_placeholder();
			placeholder = !placeholder;
			node->set_scene_instance_load_placeholder(placeholder);
			scene_tree->update_tree();
		}
	}
}
void SceneTreeDock::_toggle_editable_children(Node *p_node) {