[HOUSEKEEPING] Remove CLI arguments and related cleanups post 26.1.0

[tbenr]

We should remove --Xp2p-reworked-sidecar-custody-sync-enabled once it is default for 1 or 2 releases.

This also imply removal of isEarliestAvailableDataColumnSlotSupported in CombinedChainDataClient
and delete DasCustodySync too.

Than we should rename --Xp2p-reworked-sidecar-custody-sync-* params to --Xp2p-sidecar-custody-sync-*