Added a class to the loading paragraph and updating styling to class
instead of generically all child paragraphs of .loading

• update p to class next-step (currently unique class in static)

https://www.agileplannerapp.com/boards/105200/cards/5835
Merge pull request #463 from alphagov/fix-smartanswers-jittery-paragraphs

Added a class to the loading paragraph (smartanswers) and updating styling to match