[extractor/NZOnScreen] Add extractor (#6208)

Authored by: gregsadetsky, pukkandan
Closes #6193

yt_dlp/extractor/_extractors.py

@@ -1287,6 +1287,7 @@ from .nytimes import (
 )
 from .nuvid import NuvidIE
 from .nzherald import NZHeraldIE
+from .nzonscreen import NZOnScreenIE
 from .nzz import NZZIE
 from .odatv import OdaTVIE
 from .odnoklassniki import OdnoklassnikiIE