### Tested versions

Caused by [0d6300d269b818e6c3d3ea9cbc592480103aa6d0] Fix folder color not showing up in file dialogs
https://github.com/godotengine/godot/pull/84837
(git bisection)

### System information

Godot v4.3.dev (6faa5c6dc) - Fedora Linux 39 (Workstation Edition) - Wayland - Vulkan (Forward+) - dedicated AMD Radeon RX Vega (RADV VEGA10) () - AMD Ryzen 7 5800X 8-Core Processor (16 Threads)

### Issue description

When opening the export path, it results in a black popup.

![image](https://github.com/godotengine/godot/assets/270928/d67dee6a-f1e1-4bf3-8a3f-419554269f4a)


### Steps to reproduce

1. Open export settings
2. Add an export target
3. Try to select an export path

### Minimal reproduction project (MRP)

n/a
ConfirmationDialog::_post_popup();
	
	String current = dir_access->get_current_dir();
	while (!dir_access->dir_exists(current)) {
		current = current.get_base_dir();
	}
	set_current_dir(current);
	if (mode == FILE_MODE_SAVE_FILE) {
		file->grab_focus();
	} else {
		item_list->grab_focus();
	}
	if (mode == FILE_MODE_OPEN_DIR) {
		file_box->set_visible(false);
	} else {
		file_box->set_visible(true);
	}
	if (!get_current_file().is_empty()) {
		_request_single_thumbnail(get_current_dir().path_join(get_current_file()));
	}
	local_history.clear();
	local_history_pos = -1;
	_push_history();
	set_process_shortcut_input(true);
}
void EditorFileDialog::_thumbnail_result(const String &p_path, const Ref<Texture2D> &p_preview, const Ref<Texture2D> &p_small_preview, const Variant &p_udata) {