chore(l1): register block building metric and dashboard (#4879)

**Motivation**
In #4878 we forgot to register the metric so prometheus picks it up

<img width="2220" height="338" alt="image"
src="https://github.com/user-attachments/assets/83d24e97-9d68-41b3-88f6-cd0fdfb8d626"
/>

Author: edg-l

crates/blockchain/metrics/metrics_blocks.rs

@@ -105,8 +105,14 @@ impl MetricsBlocks {
             .map_err(|e| MetricsError::PrometheusErr(e.to_string()))?;
         r.register(Box::new(self.gigagas.clone()))
             .map_err(|e| MetricsError::PrometheusErr(e.to_string()))?;
+        r.register(Box::new(self.gigagas_block_building.clone()))
+            .map_err(|e| MetricsError::PrometheusErr(e.to_string()))?;
         r.register(Box::new(self.gas_used.clone()))
             .map_err(|e| MetricsError::PrometheusErr(e.to_string()))?;
+        r.register(Box::new(self.block_building_base_fee.clone()))
+            .map_err(|e| MetricsError::PrometheusErr(e.to_string()))?;
+        r.register(Box::new(self.block_building_ms.clone()))
+            .map_err(|e| MetricsError::PrometheusErr(e.to_string()))?;
 
         let encoder = TextEncoder::new();
         let metric_families = r.gather();