Return 400 for execution payload bids ignored by gossip validation

[hangleang]

No description provided.

[povi]

I wouldn't return Bad Request to valid data, e.g. it's not the winning bid (highest value). It's just not fair. The sender doesn't even know what is the winning bid on the beacon node, and is left thinking the data sent is bad, when its not.

I think the problem is that gossip check actions (accept/ignore/reject) doesn't accurately match HTTP response codes. Some ignore actions maybe deserve 4xx statuses - like the bid is not compatible with the current head branch. Others do not.

[povi]

What is the use case that you need 400 status for ignored bids?

[hangleang]

What is the use case that you need 400 status for ignored bids?

I was testing #948 with buildoor submitted its p2p bids with the wrong fee recipient. Grandine beacon node ignored all of them, so none were broadcast, yet it returned 200 each time, which made the builder think its bid was published. The endpoint specifies The bid was validated successfully and has been broadcast. for 200 response.

I agree it is unfair for those valid cases you mentioned, maybe we should add a variant for "valid but not propagated"?