Refactor import statement for getUserAgent in contentstack.js

Author: nadeem-cs

lib/contentstack.js

@@ -4,7 +4,7 @@
  */
 import packages from '../package.json'
 import clonedeep from 'lodash/cloneDeep'
-import getUserAgent, { getRegionEndpoint } from './core/Util.js'
+import getUserAgent from './core/Util.js'
 import contentstackClient from './contentstackClient.js'
 import httpClient from './core/contentstackHTTPClient.js'
 const regionHostMap = {