### 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
res = new_res;
							}
							break;
						}
					}
					
					if (res.is_valid() && !res->get_path().is_resource_file() && _export_customize_object(res.ptr(), customize_resources_plugins), true) {
						changed = true;
					}
				}
			} break;
			case Variant::DICTIONARY: {
				Dictionary d = v;
				if (_export_customize_dictionary(d, customize_resources_plugins)) {
					changed = true;
				}
			} break;
			case Variant::ARRAY: {
				Array a = v;
				if (_export_customize_array(a, customize_resources_plugins)) {
					changed = true;
				}
			} break;
			default: {
			}
		}
	}
	return changed;
}
bool EditorExportPlatform::_export_customize_object(Object *p_object, LocalVector<Ref<EditorExportPlugin>> &customize_resources_plugins) {