getDesignTimeVariant(mPropertyBag) {
			if (!mPropertyBag.id) {
				return Promise.reject("App Variant ID must be provided");
			}
			return AppVariantFactory.load(mPropertyBag);
		}
Returns the design time representation of the app variant.
@param {object} mPropertyBag - Object with parameters as properties
@param {string} mPropertyBag.id - App variant ID
@returns {Promise<object>} Resolving with the loaded variant
@private
@ui5-restricted