horizon state verification always disabled since protocol 19

[leighmcculloch]

I was working in an area of the start script and noticed the following lines:

https://github.com/stellar/quickstart/blob/fc19970668cacbdff5a26125984ff707c3414d04/start#L533-L537

This logic has existed since https://github.com/stellar/quickstart/pull/373, which was the start of soroban support, very likely before Horizon supported state verification of protocol 19.

@stellar/platform-eng Should those lines be removed now? Or do we generally not want state verification enabled since protocol 19?