Behavior change: Ticket cleanup mechanism

**Goal of this issue:**
Opened this issue to track if there is any feedback against this behavior change.

**Background:**
Open Match has a ticket auto-expiring mechanism since v0.4.0. However, this expiration logic will introduce some memory leak in Redis so starting from v0.10.0, we will remove the ticket auto-expiring logic from our statestore implementation in googleforgames/open-match#1146. After this change, users are now responsible for deleting any unused/invalid tickets that have created in Open Match.

**TODOs:**
Document this behavior change in v0.10 release and the ticket cleanup mechanism in Open Match