fix: correctly get signature from single attestation bytes

[nflaig]

Motivation

Need to correctly handle extracting signature from single attestation

Description

Use getSignatureFromSingleAttestationSerialized to extract signature from bytes for post-electra single attestations

Closes #7259

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 48.43%. Comparing base (cfe6c89) to head (655cd74).
Report is 2 commits behind head on devnet-5.

Additional details and impacted files

@@             Coverage Diff              @@
##           devnet-5    #7266      +/-   ##
============================================
- Coverage     48.44%   48.43%   -0.01%     
============================================
  Files           602      602              
  Lines         40321    40323       +2     
  Branches       2057     2057              
============================================
  Hits          19532    19532              
- Misses        20751    20753       +2     
  Partials         38       38              

[ensi321]

Personally would like to see the fork switching logic to be hidden in sszBytes.ts

Maybe a function named getSignatureFromBeaconAttestationSerialized in a similar fashion as getBlockRootFromBeaconAttestationSerialized.

[nflaig]

was debating that as well but figured we only use those in network processor and this pattern was used before already so I went with explicit fork logic in validation itself

lodestar/packages/beacon-node/src/chain/validation/attestation.ts

Lines 265 to 267 in 957684f

	const committeeIndexForLookup = isForkPostElectra(fork)
	? (getCommitteeIndexFromAttestationOrBytes(fork, attestationOrBytes) ?? 0)
	: PRE_ELECTRA_SINGLE_ATTESTATION_COMMITTEE_INDEX;

Either one seems fine to me

[wemeetagain]

🎉 This PR is included in v1.26.0 🎉