Adds `enterPictureInPictureReason` to the `MediaSessionActionDetails` sent to the `enterpictureinpicture` action in the Media Session API. This allows developers to distinguish between `enterpictureinpicture` actions triggered explicitly by the user (e.g. from a button in the user agent) and `enterpictureinpicture` actions triggered automatically by the user agent due to the content becoming occluded.
This allows developers to distinguish between `enterpictureinpicture` actions triggered explicitly by the user (e.g. from a button in the user agent) and `enterpictureinpicture` actions triggered automatically by the user agent due to the content becoming occluded.