### Godot version

any version after 74458b6

### System information

Linux x64, but likely irrelevant

### Issue description

OpenXR action maps are not properly exported in recent builds of Godot 4: the `.res` file is small and does no longer seem to contain anything of use. In-game, no actions are passed on to OpenXR (obviously).

I bisected the issue down to https://github.com/godotengine/godot/commit/74458b6e9bed0f28db3374c7406eacbcf4b09b9d, which was merged in #70377.

### Steps to reproduce

1. Delete any previous export files (`.godot/exported/*/*.pkg`)
2. Perform an export (I did one for Android, but it likely works with anything)
3. Observe OpenXR actions not working in the export (error spam 'sync_action_sets: Condition "active_sets.size() == 0"'), and the exported action map file being very small (`.godot/exported/*/*.pkg`, from a few tens of kilobytes down to 296 bytes)

### Minimal reproduction project

Any OpenXR project can be used, such as https://github.com/BastiaanOlij/godot4_openxr_demo
while (p_node != nullptr && p_node != p_root) {
		if (p_root->is_editable_instance(p_node)) {
			return true;
		}
		p_node = p_node->get_owner();
	}
	return false;
}
bool EditorExportPlatform::_export_customize_scene_resources(Node *p_root, Node *p_node, LocalVector<Ref<EditorExportPlugin>> &customize_resources_plugins) {
	bool changed = false;
	if (p_root == p_node || p_node->get_owner() == p_root || _is_editable_ancestor(p_root, p_node)) {
		if (_export_customize_object(p_node, customize_resources_plugins)) {
			changed = true;
		}
	}
	for (int i = 0; i < p_node->get_child_count(); i++) {
		if (_export_customize_scene_resources(p_root, p_node->get_child(i), customize_resources_plugins)) {
			changed = true;
		}
	}
	return changed;
}
String EditorExportPlatform::_export_customize(const String &p_path, LocalVector<Ref<EditorExportPlugin>> &customize_resources_plugins, LocalVector<Ref<EditorExportPlugin>> &customize_scenes_plugins, HashMap<String, FileExportCache> &export_cache, const String &export_base_path, bool p_force_save) {