Some bug fixes

I realised I didn’t do a very thorough job at testing the last update for the Squat Challenge, so here are a few follow up fixes :)

1. The signup UI wasn’t showing the privacy policy or terms and conditions that it was asking you to agree to (sorry about that)
2. The UI for building custom workouts wasn’t showing the exercise categories on the left or the descriptions of exercises when they were selected
3. The Y-axis scale for the Squat Challenge chart should be a bit less busy now - I hadn’t expected so many squats already! :)