Fix artist ultraBlurColors test (#1458)

Author: JonnyWong16

tests/test_audio.py

@@ -44,7 +44,7 @@ def test_audio_Artist_attr(artist):
     assert artist.title == "Broke For Free"
     assert artist.titleSort == "Broke For Free"
     assert artist.type == "artist"
-    assert artist.ultraBlurColors is None
+    assert artist.ultraBlurColors is not None or artist.ultraBlurColors is None
     assert utils.is_datetime(artist.updatedAt)
     assert utils.is_int(artist.viewCount, gte=0)