Remove or feature gate test CLI flags before PeerDAS release

[jimmygchen]

A few test CLI flags are being added as part of testing PeerDAS, these are for devnet testing only, and should be removed from the unstable branch before the PeerDAS mainnet release once it's no longer needed.

This includes:

• --malicious-withhold-count
• Add CLI flags to delay publishing for edge case testing on PeerDAS devnets #6919
• Add a beacon node flag to advertise a false custody group count for testing #6973

If it's useful for future DAS testing, we could probably keep them with feature gates.