Make expiration time for unconfirmed tracked runs configurable

Problem

If a team leaves an unconfirmed tracked run open for an extended period (e.g., a week), it will expire and cannot be replayed. In this case, if new changes are merged in afterwards, the team loses the ability to confirm or replay the original tracked run in its original context. The lack of configurability around expiration time makes it easy for teams to lose work or be forced into re-running pipelines against an unintended state. Additionally, there is no documentation available that explains the default expiration settings or whether they can be changed.