tavernVideo is already set to required.
This check is needed to correctly handle tavern building on map.
LOCPLINT->castleInt checks, that we deal with tavern in town.
If not than we play standard video, as tavern object on map is not handled by faction config.
Maybe LOCPLINT->castleInt->town->town->clientInfo.tavernVideo!="" is excessive (legacy) check and be deleted. But there is no check for video format ("animationFormat" didn't checked existence of videoTavern mentioned in json, so it's better to leave this check until video files paths will be handled in term of existence.