Handle new error response format on frontend.

-----------------------
After the introduction of new exception classes on backend the error response format is changed. As in new error response error subcode should be accessed on error.sub_code this commit handles this case.
Also change in subcode to identify project is private and cannot be accessed by user has been addressed.

Author: Aadesh-Baral

frontend/src/utils/promise.js

@@ -24,7 +24,7 @@ export async function handleErrors(response) {
     .clone()
     .json()
     .then((res) => {
-      text = res.SubCode || response.statusText;
+      text = res.error?.sub_code || res.SubCode || response.statusText;
     });
   throw Error(text);
 }

frontend/src/views/project.js

@@ -198,7 +198,7 @@ export const ProjectDetailPage = () => {
       )}
       {error && (
         <>
-          {error.message === 'PrivateProject' ? (
+          {error.message === 'PRIVATE_PROJECT_NOT_ALLOWED' ? (
             <PrivateProjectError />
           ) : (
             <NotFound projectId={id} />