add json schema allowPublicAccess

src/Umbraco.Web.UI.Client/src/packages/core/extension-registry/umbraco-package.ts

@@ -27,6 +27,12 @@ export interface UmbracoPackage {
 	 */
 	allowTelemetry?: boolean;
 
+	/**
+	 * @title Decides if the package is allowed to be accessed by the public, e.g. on the login screen
+	 * @default false
+	 */
+	allowPublicAccess?: boolean;
+
 	/**
 	 * @title An array of Umbraco package manifest types that will be installed
 	 * @required