### Godot version

v4.0.beta17.mono.official [c40020513]

### System information

Window 11, Forward+, GTX 1060

### Issue description

Adding two theme variations in a row result to a  crash.

https://user-images.githubusercontent.com/93253123/217037249-1ce1d56d-beb6-4435-83ad-9f8a07fe0e96.mp4



### Steps to reproduce

1. Create a project.
2. Create a theme.
3. Double click to go in the theme editor.
4. Click on manage items buttons.
5. In the add type field type a name to add a type.
6. type another name to add a second type.
7. Crash.

### Minimal reproduction project

[ThemeVariationCrash.zip](https://github.com/godotengine/godot/files/10665863/ThemeVariationCrash.zip)

VBoxContainer *root_vbox = array_prefix.is_empty() ? main_vbox : editor_inspector_array_per_prefix[array_prefix]->get_vbox(array_index);
		if (!root_vbox) {
			continue;
		}
		if (!vbox_per_path.has(root_vbox)) {
			vbox_per_path[root_vbox] = HashMap<String, VBoxContainer *>();
			vbox_per_path[root_vbox][""] = root_vbox;
		}
		VBoxContainer *current_vbox = root_vbox;
		String acc_path = "";
		int level = 1;
		Vector<String> components = path.split("/");
		for (int i = 0; i < components.size(); i++) {
			String component = components[i];
			acc_path += (i > 0) ? "/" + component : component;
			if (!vbox_per_path[root_vbox].has(acc_path)) {
				
				EditorInspectorSection *section = memnew(EditorInspectorSection);
				current_vbox->add_child(section);
				sections.push_back(section);
				String label;
				String tooltip;
				
				EditorPropertyNameProcessor::Style section_name_style = property_name_style;
				if ((p.usage & PROPERTY_USAGE_SCRIPT_VARIABLE) && section_name_style == EditorPropertyNameProcessor::STYLE_LOCALIZED) {
					section_name_style = EditorPropertyNameProcessor::STYLE_CAPITALIZED;
				}
				
				if ((i == 0 && component == group) || (i == 1 && component == subgroup)) {
					if (section_name_style == EditorPropertyNameProcessor::STYLE_LOCALIZED) {