The new `L1CrossDomainMessenger` is no longer ownable so we no
longer need to transfer the ownership to the dictator as part
of the system upgrade. The dictator does not need ownership
of the old contract because it doesn't call `pause` on the
`L1CrossDomainMessenger` anymore as part of the on chain upgrade.
Instead, the pausable functionality is in the `OptimismPortal`
which is set with a constructor arg and its pausability can
be toggled using functions on the portal.