chore(op-service): reduce allocations (#10331)

* refactor: improve perf

* improve perf

* rollback

* rollback

---------
Co-authored-by: Khanh Hoa <khanhoait.bka@gmail.com>

op-service/metrics/doc/cmd.go

@@ -46,7 +46,7 @@ func NewSubcommands(m Metrics) cli.Commands {
 				table.SetCenterSeparator("|")
 				table.SetAutoWrapText(false)
 				table.SetHeader([]string{"Metric", "Description", "Labels", "Type"})
-				var data [][]string
+				data := make([][]string, 0, len(supportedMetrics))
 				for _, metric := range supportedMetrics {
 					labels := strings.Join(metric.Labels, ",")
 					data = append(data, []string{metric.Name, metric.Help, labels, metric.Type})

op-service/txmgr/txmgr.go

@@ -323,7 +323,7 @@ func (m *SimpleTxManager) craftTx(ctx context.Context, candidate TxCandidate) (*
 // data.
 func MakeSidecar(blobs []*eth.Blob) (*types.BlobTxSidecar, []common.Hash, error) {
 	sidecar := &types.BlobTxSidecar{}
-	blobHashes := []common.Hash{}
+	blobHashes := make([]common.Hash, 0, len(blobs))
 	for i, blob := range blobs {
 		rawBlob := *blob.KZGBlob()
 		sidecar.Blobs = append(sidecar.Blobs, rawBlob)