Fix NoneType attribute error in np.py

[albertsj1]

This fixes the following error in np.py if no track is currently playing.

./np.py
Traceback (most recent call last):
  File "np.py", line 113, in <module>
    main()
  File "np.py", line 83, in main
    output(is_track_loved(now_playing))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "np.py", line 45, in is_track_loved
    text = f"{track.artist} - {colored(track.title, attrs=['bold'])}"
              ^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'artist'

Instead, No track currently playing is displayed.

[hugovk]

Thank you!