### 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
if (selected_shader_material.is_null()) {
		return;
	}
	Ref<Shader> existing = selected_shader_material->get_shader();
	EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
	undo_redo->create_action(TTR("Set Shader"));
	undo_redo->add_do_method(selected_shader_material.ptr(), "set_shader", p_shader);
	undo_redo->add_undo_method(selected_shader_material.ptr(), "set_shader", existing);
	undo_redo->commit_action();
}
void SceneTreeDock::_script_creation_closed() {
	script_create_dialog->disconnect("script_created", callable_mp(this, &SceneTreeDock::_script_created));
	script_create_dialog->disconnect("confirmed", callable_mp(this, &SceneTreeDock::_script_creation_closed));
	script_create_dialog->disconnect("canceled", callable_mp(this, &SceneTreeDock::_script_creation_closed));
}
void SceneTreeDock::_shader_creation_closed() {