Fix ui host for oauth

Author: harshithad0703

lib/core/contentstackHTTPClient.js

@@ -79,10 +79,10 @@ export default function contentstackHttpClient (options) {
 
   let uiHostName, developerHubBaseUrl
   if (config.host && (config.host.startsWith('dev') || config.host.startsWith('stag'))) {
+    uiHostName = config.host.replace('-api.', '-app.')
     const transformedHost = config.host
       .replace(/^dev\d+/, 'dev')
       .replace(/^stag\d+/, 'stag')
-    uiHostName = transformedHost.replace('-api.', '-app.')
     developerHubBaseUrl = `https://${transformedHost.replace('-api.', '-developerhub-api.')}`
   } else {
     uiHostName = getRegionEndpoint(region, 'application')