Remove daml3-script JSON Ledger Client

[samuel-williams-da]

Remove the daml3-script JsonLedgerClient, and all flags that align to it.

Following #17974, the refined script submission logic can also be simplified. There are a few other places where logic can be simplified once this client is gone.

[basvangijzel-DA]

Paul: Marcin might have migrated this to the new JSON client. Double check what needs to happen with Script.