add a metric to measure the attestation gossip validator (#15785)

This PR adds a Summary metric to measure the p2p topic validation time
for attestations arriving from the network. It times the
`validateCommitteeIndexBeaconAttestation` method.

The metric is called `gossip_attestation_verification_milliseconds`

**Acknowledgements**

- [x] I have read
[CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
- [x] I have included a uniquely named [changelog fragment
file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
- [x] I have added a description to this PR with sufficient context for
reviewers to understand this PR.

---------

Co-authored-by: Kasey Kirkham <kasey@users.noreply.github.com>

beacon-chain/sync/metrics.go

@@ -133,6 +133,12 @@ var (
 			Help: "Time to verify gossiped attestations",
 		},
 	)
+	attestationVerificationGossipSummary = promauto.NewSummary(
+		prometheus.SummaryOpts{
+			Name: "gossip_attestation_verification_milliseconds",
+			Help: "Time to verify gossiped attestations",
+		},
+	)
 	blockVerificationGossipSummary = promauto.NewSummary(
 		prometheus.SummaryOpts{
 			Name: "gossip_block_verification_milliseconds",

beacon-chain/sync/validate_beacon_attestation.go

@@ -7,6 +7,7 @@ import (
 	"reflect"
 	"slices"
 	"strings"
+	"time"
 
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/blockchain"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/blocks"
@@ -41,6 +42,11 @@ func (s *Service) validateCommitteeIndexBeaconAttestation(
 	pid peer.ID,
 	msg *pubsub.Message,
 ) (pubsub.ValidationResult, error) {
+	start := time.Now()
+	defer func() {
+		attestationVerificationGossipSummary.Observe(float64(time.Since(start).Milliseconds()))
+	}()
+
 	if pid == s.cfg.p2p.PeerID() {
 		return pubsub.ValidationAccept, nil
 	}

changelog/bharath_add-metric-for-attestation-gossip-verification.md

@@ -0,0 +1,2 @@
+### Added
+- prometheus metric `gossip_attestation_verification_milliseconds` to track attestation gossip topic validation latency.