Adds an event handler that runs when the playback is paused.
A video in a video box is paused when a site visitor clicks the video box's
pause button or by calling its pause() or stop() functions.
handler(event: Event): void The name of the function or
the function expression to run when the video is paused.
This method doesn’t return any custom errors, but may return standard errors. Learn more about standard Wix errors.