Add LeaseState.CANCELLED.value to active_states

Before raising this MR, consider whether the following are required, and complete if so:

• Unit tests
• Metrics
• Documentation update(s)

Description

Please provide a description of this merge request and outline some of the background / context to the changes proposed.

Changes proposed in this merge request:

• Add LeaseState.CANCELLED.value to active_states so it can be passed to workers
• Add order_by clause when joining active leases, to ensure the the first lease in the list is the most recent one

Issues addressed

#400 (closed)