3.9.0

refactor: follow the embedded event rename to embeddedCloseRequested

The event the tutorials listen for to take their screen back is now
embeddedCloseRequested: the participant asks to close OpenVidu Meet, and the
tutorial removes the component. viewClosed never shipped.

The listener comments no longer say the component or the meeting is closed,
matching the code blocks on openvidu.io, and the test runner README names the
canonical events and command the suites rely on instead of the 3.8.0 ones.