fix: metrics on nil data

Author: julienrbrt

block/internal/executing/executor.go

@@ -658,6 +658,9 @@ func (e *Executor) sendCriticalError(err error) {
 
 // recordBlockMetrics records metrics for the produced block
 func (e *Executor) recordBlockMetrics(data *types.Data) {
+	if data == nil || data.Metadata == nil {
+		return
+	}
 	e.metrics.NumTxs.Set(float64(len(data.Txs)))
 	e.metrics.TotalTxs.Add(float64(len(data.Txs)))
 	e.metrics.BlockSizeBytes.Set(float64(data.Size()))