Fix ui host for oauth

Author: harshithad0703

lib/core/contentstackHTTPClient.js

@@ -77,19 +77,16 @@ export default function contentstackHttpClient (options) {
     }
   }
 
-  const uiHostName = getRegionEndpoint(region, 'application')
-
-  let developerHubBaseUrl
+  let uiHostName, developerHubBaseUrl
   if (config.host && (config.host.startsWith('dev') || config.host.startsWith('stag'))) {
-    developerHubBaseUrl = config.host
-      .replace('api', 'developerhub-api')
+    const transformedHost = config.host
       .replace(/^dev\d+/, 'dev')
       .replace(/^stag\d+/, 'stag')
-      .replace(/^http:\/\//, '')
-      .replace(/^https:\/\//, '')
-      .replace(/^/, 'https://')
+    uiHostName = transformedHost.replace('-api.', '-app.')
+    developerHubBaseUrl = `https://${transformedHost.replace('-api.', '-developerhub-api.')}`
   } else {
-    developerHubBaseUrl = getRegionEndpoint(region, 'developerHub').replace(/^/, 'https://')
+    uiHostName = getRegionEndpoint(region, 'application')
+    developerHubBaseUrl = `https://${getRegionEndpoint(region, 'developerHub')}`
   }
 
   const uiBaseUrl = config.endpoint || `${protocol}://${uiHostName}`