If a recording is in progress, and the moderator leaves, use `askOnUnload` to confirm exit

It is undesirable to turn off recording if the moderator leaves, as they may wish recording to continue.

So, recording doesn't stop until either the moderator stops in manually, or the last person leaves the room; however, until recording stops, it isn't available for download by the moderator.

This check *reminds* the moderator of this interaction...