Ignore known blocks submitted through API

[eth2353]

Describe the bug

I believe this is a similar issue to #6021 - the beacon node API returns an error ( BLOCK_ERROR_ALREADY_KNOWN ) when a validator client submits a block that the beacon node has already seen. We see this happening in our DVT setup.

Expected behavior

Ideally it would not return with an error status code, since nothing went "really wrong". Would be great if this error could be "ignored" too.

Steps to reproduce

No response

Additional context

Error: BLOCK_ERROR_ALREADY_KNOWN error: Gossip validations failed while publishing the block broadcastValidation=gossip, blockRoot=0x7d24e12894a9cfd45aaf2dd3639c472cba9768c49ca7efba8329f5c0e7309162, bodyRoot=0x920d9d0b98ebe4aaaeb5e8ad91b7eef64b7f55e011877f8a2e31cfc275f0adad, blockLocallyProduced=false, slot=939786, code=BLOCK_ERROR_ALREADY_KNOWN, root=0x7d24e12894a9cfd45aaf2dd3639c472cba9768c49ca7efba8329f5c0e7309162 error: Req req-8xfv publishBlindedBlockV2 error code=BLOCK_ERROR_ALREADY_KNOWN, root=0x7d24e12894a9cfd45aaf2dd3639c472cba9768c49ca7efba8329f5c0e7309162

Operating system

Linux

Lodestar version or commit hash

v1.15.0/5d93a62

[nflaig]

Thanks for reporting this!

I thought this was already covered by https://github.com/ChainSafe/lodestar/pull/5714 and https://github.com/ChainSafe/lodestar/pull/5405 but it looks like we only ignore if we publish a blinded block. Should be easy to fix.