Check pending deposits before applying builder deposits

[terencechain]

Add IsPendingValidator check to processDepositRequest so that deposit requests with builder credentials are routed to the validator pending queue when a pending deposit with a valid signature already exists for the same pubkey

Also updated spec test to alpha3 so we can merge this with green CI/CD

[nalepae]

Why not merging these 2 changelogs in a single changelog file?

[nalepae]

Do we really want to silence this error?
I understand we do not want to immediately return in such a case, but maybe could we print a WARNING/ERROR log?

[nalepae]

I feel the whole function (less complex conditions) would be simpler with:

func applyBuilderDepositRequest(beaconState state.BeaconState, request *enginev1.DepositRequest) (bool, error) {
	if beaconState.Version() < version.Gloas {
		return false, nil
	}

	pubkey := bytesutil.ToBytes48(request.Pubkey)
	idx, isBuilder := beaconState.BuilderIndexByPubkey(pubkey)
	if isBuilder {
		if err := beaconState.IncreaseBuilderBalance(idx, request.Amount); err != nil {
			return false, fmt.Errorf("increase builder balance: %w", err)
		}
		return true, nil
	}

	isBuilderPrefix := helpers.IsBuilderWithdrawalCredential(request.WithdrawalCredentials)
	_, isValidator := beaconState.ValidatorIndexByPubkey(pubkey)
	if !isBuilderPrefix || isValidator {
		return false, nil
	}

	isPending, err := beaconState.IsPendingValidator(request.Pubkey)
	if err != nil {
		return false, fmt.Errorf("check pending validator: %w", err)
	}
	if isPending {
		return false, nil
	}

	if err := applyDepositForNewBuilder(
		beaconState,
		request.Pubkey,
		request.WithdrawalCredentials,
		request.Amount,
		request.Signature,
	); err != nil {
		return false, fmt.Errorf("apply deposit for new builder: %w", err)
	}

	return true, nil
}

[nalepae]

Not related to this PR, but it seems that the builderDepositsProcessedTotal metric is increases, event the deposit processed is NOT from a builder.