Update the ‘Confirm your service is unique’ guidance

[karlchillmaid]

One of the mandatory tasks we make users complete before they go live is ‘Confirm your service is unique’.

We introduced this page as part of the ‘onboarding’ epic. It was good enough for MVP, but now it needs to change.

It’s biggest weaknesses are:

• the concept of a ‘unique service’ is abstract
• we don’t explain why we want your service to be ‘unique’ (the free allowance)
• there’s a disconnect between the title/h2 and the interaction (text field, green button)

The new page design:

• makes a stronger connection between the title/h1 and the interaction
• explains that this is all about the free allowance

It’s not perfect, but it’s a reasonable first step and sets us up well for the work we’ll do in Q2.

This PR also changes the link on the ‘Make your service live’ task list page, so it matches the new h1.

[saimaghafoor]

reviewed - comment on service being one of its kind