Create 1 Study Session Experience

There are 2 ways to start a study session.

1. from /flashcards page
- doesn't give user the option to choose study directions, always see front guess back
- user is able to see results from most recent session
- user is shown results from most recent session when they click past sessions
- doesn't route to /study/results/[sessionId]
2. from /study pageBoth starting locations should provide the same experience
- user is given the option to choose study directions, can guess front or back
- user is NOT able to see results from any sessions
- results UI is shown without data
- doesn't route to /study/results/[sessionId]