backend-defaults: add via to credentials

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: Patrik Oldsberg <poldsberg@gmail.com>
Signed-off-by: Vincenzo Scamporlino <vincenzos@spotify.com>

packages/backend-plugin-api/src/services/definitions/AuthService.ts

@@ -35,6 +35,8 @@ export type BackstageUserPrincipal = {
    * The entity ref of the user entity that this principal represents.
    */
   userEntityRef: string;
+
+  via?: BackstageServicePrincipal;
 };
 
 /**