If the User wants to close (hide) the banner on the Default dashboard, he/she should click on X button. The banner should not be displayed again for the user (once per user).

https://www.figma.com/file/hVo2gpt7bDAPeAkhuzfVSf/Customizable-dashboard?type=design&node-id=2500%3A242289&mode=design&t=arPDaLY9HB52mnVw-1 

Banner:

• is displayed when user doesn't have customized dashboard until is closed by user (will never be displayed again, user has an option to customize by "More" button)
• should not be displayed after customization of the dashboard
  So basically it is shown only before customization if the user didn't close it.