title: Handle legacy lease swaps on coretime

doc:
  - audience: Runtime Dev
    description: |
      When a `registar::swap` extrinsic is executed it swaps two leases on the relay chain but the
      broker chain never knows about this swap. This change notifies the broker chain via a XCM
      message for a swap so that it can update its state.
crates:
  - name: pallet-broker