Write brief for Frontend retest

[kellylee-gds]

What

Draft a brief for the re-test of GOV.UK Frontend.

Why

To give DAC context when conducting the re-test.

Who needs to work on this

Kelly or Charlotte

Who needs to review this

Owen, beeps or Anika

Done when

• brief has been drafted and review app examples have been added #5085
• brief has been reviewed by the team
• brief has been shared with DAC