[#8927] Add in click tracking to 'Start again' links

- https://www.agileplannerapp.com/boards/105200/cards/8927
- In order to understand our current usage on 'Start again' links in smart answers, we should set up and deploy event tracking on these links
- This should help us when making decisions relating to this kind of interaction in the future
Merge pull request #1371 from alphagov/feature/add-start-again-link-tracking

[#8927] Add in click tracking to 'Start again' links