### Godot version

4.1 rc3

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

This™
![image](https://github.com/godotengine/godot/assets/2223172/cb33110f-a5b0-400a-951f-3fa425f05714)

It can still happen, but it's more difficult to trigger.

### Steps to reproduce

1. Create a new scene with a Control node
2. Add Theme to the Control
3. Open Theme Editor
4. Clear the `theme` property in Control
5. Save, with Theme Editor opened
6. Restart

### Minimal reproduction project

N/A
for (int i = 0; i < plugins_list.size(); i++) {
		plugins_list[i]->forward_3d_draw_over_viewport(p_overlay);
	}
}
void EditorPluginList::forward_3d_force_draw_over_viewport(Control *p_overlay) {
	for (int i = 0; i < plugins_list.size(); i++) {
		plugins_list[i]->forward_3d_force_draw_over_viewport(p_overlay);
	}
}
void EditorPluginList::add_plugin(EditorPlugin *p_plugin) {
	ERR_FAIL_COND(plugins_list.has(p_plugin));
	plugins_list.push_back(p_plugin);
}
void EditorPluginList::remove_plugin(EditorPlugin *p_plugin) {
	plugins_list.erase(p_plugin);
}
bool EditorPluginList::is_empty() {
	return plugins_list.is_empty();
}
void EditorPluginList::clear() {
	plugins_list.clear();
}
EditorPluginList::EditorPluginList() {
}
EditorPluginList::~EditorPluginList() {
}