Orchestrator's `rebase` protection broken due to EIP-7702

[pmerkleplant]

The orchestrator performs a check in rebase() trying to prevent contracts from executing the rebase. IIUC the idea behind this is to prevent sandwiching AMPL's supply adjustment.

https://github.com/ampleforth/ampleforth-contracts/blob/1d13ed3bcd32772ddba91355579b87d07e3551db/contracts/Orchestrator.sol#L44

However, since the Pectra fork launched on Ethereum mainnet it's possible for EOAs to have executable logic, see EIP-7702. This update renders the check mostly useless.