GRTLV-332 replace notification banner with Design System notification banner component

[boxadesign]

What

Replace the existing govuk notification banner with the Great Design System notification banner component

To test:

• Book an event and observe the success banner.
• Cancel an event
• Contact form submission - http://cms.trade.great:8020/contact/domestic/export-support/export-enquiry-submitted/
• EYB - Expansion guide created - http://cms.trade.great:8020/international/expand-your-business-in-the-uk/guide/
• EYB - Email address confirmed
• EYB - Signed back in - about your business

Workflow

• Ticket exists in Jira https://uktrade.atlassian.net/browse/GRTLV-332
• Jira ticket has the correct status.
• A clear/description pull request messaged added.

Security

• Frontend assets have been re-compiled

Merging

• This PR can be merged by reviewers. (If unticked, please leave for the author to merge)