fix: expand successful status range to include 300-399 status code to…

… allow for 304 , see

https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/304

packages/oidc_core/lib/src/endpoints/facade.dart

@@ -29,7 +29,7 @@ class OidcEndpoints {
           rawResponse: response,
         );
       }
-      if (!(response.statusCode >= 200 && response.statusCode < 300)) {
+      if (!(response.statusCode >= 200 && response.statusCode < 400)) {
         throw OidcException(
           'Failed to handle the response from endpoint (status code ${response.statusCode}): ${request.url}',
           rawRequest: request,