Replace `species_list: 3` with list label in all test files
Replace `species_list: 3` with list label in all test files

  Makes `test_image_with_observations_in_species_list`, and
  anticipates problems in other test methods.

pellaea/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,JoeCohen/mushroom-observer,raysuelzer/mushroom-observer,JoeCohen/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer,raysuelzer/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer