Create a banner to display success from purchasing CI Minutes. ### Criteria || |-| || The banner should - use the `GlAlert` component - be of type `success` - be dismissible - have title: `Thanks for your purchase!` - have content: `You have successfully purchased CI minutes. You'll receive a receipt by mail.` ### Implementation plan ||| |-|-| | Add ~backend preparatory logic and banner | gitlab-org/gitlab!66901 | | Add ~frontend logic to show banner after successful purchase | gitlab-org/gitlab!66451 |