Get active lock session

Returns the newest active lock session, including segment history. If multiple active rows exist, reads select the latest createdAt, breaking ties by highest ID; no session is modified or ended. Returns null in the data field if no session is active. By default reads your own session; pass targetUserId to read the active session of a user you have access to — e.g. a keyholder checking the lockee's lock. When the keyholder hid the timer (isTimeDisplayed: false) and the caller is not a keyholder of the session, endDate and duration are null, matching what the lockee sees on the dashboard; they become visible again once the revealTimeBeforeUnlock window starts.