How to stream a local video file during a call - example code for a watch party

We've been frustrated by the limitations of video calls, particularly when trying to watch a video simultaneously. To overcome this, we've developed a quick hack using the Daily API's startScreenShare() method, which allows us to stream local video files during calls. The hack involves uploading a local video file and creating a stream from it, sharing that stream with call participants, and ensuring compatibility across different browsers.