fix: return correct type from attestation validation when using cache

[nflaig]

Motivation

We use committeeIndex to determine if single attestation is from post-electra

lodestar/packages/types/src/utils/typeguards.ts

Line 81 in 59b3b1e

return (singleAttestation as SingleAttestation<ForkPostElectra>).committeeIndex !== undefined;

This check itself is fine and should be sufficient based on the type but we return incorrect attestation type from validation when using the cache as it always contains the committeeIndex leading to the following error pre-electra

    at NetworkProcessor.processPendingGossipsubMessage (file:///usr/app/packages/beacon-node/src/network/processor/index.ts:438:9)
Nov-28 08:47:03.349[network]         error: Error adding unaggregated attestation to pool subnet=29 - Attestation should be type phase0.Attestation
Error: Attestation should be type phase0.Attestation
    at Object.true (file:///usr/app/packages/utils/src/assert.ts:7:13)
    at AttestationPool.add (file:///usr/app/packages/beacon-node/src/chain/opPools/attestationPool.ts:139:18)
    at Object.beacon_attestation (file:///usr/app/packages/beacon-node/src/network/processor/gossipHandlers.ts:649:57)
    at NetworkProcessor.gossipValidatorBatchFn (file:///usr/app/packages/beacon-node/src/network/processor/gossipValidatorFn.ts:36:23)
    at NetworkProcessor.processPendingGossipsubMessage (file:///usr/app/packages/beacon-node/src/network/processor/index.ts:438:9)

Description

Return correct type from attestation validation when using cache

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 15 lines in your changes missing coverage. Please review.

Project coverage is 48.42%. Comparing base (957684f) to head (e0be1ea).
Report is 1 commits behind head on devnet-5.

Additional details and impacted files

@@             Coverage Diff              @@
##           devnet-5    #7261      +/-   ##
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- Coverage     48.42%   48.42%   -0.01%     
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  Files           602      602              
  Lines         40337    40334       -3     
  Branches       2061     2057       -4     
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- Hits          19535    19532       -3     
  Misses        20764    20764              
  Partials         38       38