message: update_agent: slow down end state tick cadence
  There is no need to tick every 5 minutes once Zincati has reached
  its end state (accessible either due to disablement via config or
  waiting for rpm-ostree's finalization and reboot). Slow down to
  three hours.
  Closes
diff: @@ -20,6 +20,9 @@ use std::time::Duration;
  /// Default refresh interval for steady state (in seconds).
  pub(crate) const DEFAULT_STEADY_INTERVAL_SECS: u64 = 300; // 5 minutes.
  +/// Default refresh interval for end state (in seconds).
  +const END_INTERVAL_SECS: u64 = 10800; // 3 hours.
  +
  /// Default tick/refresh period for the state machine (in seconds).
  const DEFAULT_REFRESH_PERIOD_SECS: u64 = 300; // 5 minutes.
  @@ -343,6 +346,7 @@ impl UpdateAgentState {
  (Duration::from_secs(DEFAULT_REFRESH_PERIOD_SECS), true)
  }
  }
  + UpdateAgentState::EndState => (Duration::from_secs(END_INTERVAL_SECS), true),
  _ => (Duration::from_secs(DEFAULT_REFRESH_PERIOD_SECS), true),
  }
  }
  