Change contact details for support

Changelog: changed

ee/app/assets/javascripts/vue_shared/purchase_flow/constants.js

 import { s__ } from '~/locale';
 
 export const GENERAL_ERROR_MESSAGE = s__(
-  'PurchaseStep|An error occurred in the purchase step. If the problem persists please contact support@gitlab.com.',
+  'PurchaseStep|An error occurred in the purchase step. If the problem persists please contact at https://support.gitlab.com.',
 );