Adding class to things to do card

Adding a class to the wrapper of the Things to Do card so the entire card can be picked up for the A/B test defined in this card >> https://trello.com/c/cqioKzgY/218-activities-tours-a-b-test-cta-list-view-card

Just make sure the `.things-card--wrapper` class has been added to the same level as `.link--wrapper`.