Remove authorization on RedirectController endpoint (#15)

* Remove Authorize attribute

* Add AllowAnonymous attribute

Author: DanRJ

src/Altinn.App.Api/Controllers/RedirectController.cs

@@ -16,7 +16,7 @@ namespace Altinn.App.Api.Controllers
     /// <summary>
     /// Controller for redirect and validation of URL
     /// </summary>
-    [Authorize]
+    [AllowAnonymous]
     [AutoValidateAntiforgeryTokenIfAuthCookie]
     [Route("{org}/{app}/api/v1/redirect")]
     [ApiController]