Log the event for swiping up to dismiss a task in Overview.

Test: manual
Bug: 137777105

Demo logging for dismissing a task:
  data {
    elapsed_timestamp_nanos: 70772067228810
    atom {
      launcher_event {
        action: DISMISS_TASK
        src_state: OVERVIEW
        dst_state: BACKGROUND
        is_swipe_up_enabled: true
      }
    }
  }

Change-Id: I5569b80e2e1f35661bc5e9e343c6c298791a1ec1