### 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
Ref<EditorExportPlatform> platform = p_preset->get_platform();
	List<String> feature_list;
	platform->get_platform_features(&feature_list);
	platform->get_preset_features(p_preset, &feature_list);
	HashSet<String> result;
	for (const String &E : feature_list) {
		result.insert(E);
	}
	result.insert("template");
	if (p_debug) {
		result.insert("debug");
		result.insert("template_debug");
	} else {
		result.insert("release");
		result.insert("template_release");
	}
	if (!p_preset->get_custom_features().is_empty()) {
		Vector<String> tmp_custom_list = p_preset->get_custom_features().split(",");
		for (int i = 0; i < tmp_custom_list.size(); i++) {
			String f = tmp_custom_list[i].strip_edges();
			if (!f.is_empty()) {
				result.insert(f);
			}
		}
	}
	return result;
}
EditorExportPlatform::ExportNotifier::ExportNotifier(EditorExportPlatform &p_platform, const Ref<EditorExportPreset> &p_preset, bool p_debug, const String &p_path, int p_flags) {