fixed sphinx version metrics registration (#5546)

Author: jstuczyn

contracts/Cargo.lock

@@ -63,6 +63,7 @@ impl MixingStats {
             .or_default()
             .forward_packets
             .received += 1;
+
         *self.ingress.received_versions.entry(version).or_default() += 1;
     }
 
@@ -213,7 +214,7 @@ impl Display for PacketKind {
             PacketKind::Unknown => "unknown".fmt(f),
             PacketKind::Outfox => "outfox".fmt(f),
             PacketKind::Sphinx(sphinx_version) => {
-                write!(f, "sphinx-{sphinx_version}")
+                write!(f, "sphinx_{sphinx_version}")
             }
         }
     }

nym-node/nym-node-metrics/src/mixnet.rs

@@ -291,7 +291,13 @@ impl PrometheusMetric {
     }
 
     fn set(&self, value: i64) {
-        metrics_registry().set(&self.name(), value);
+        let reg = metrics_registry();
+        if !reg.set(&self.name(), value) {
+            if let Some(registrable) = self.to_registrable_metric() {
+                reg.register_metric(registrable);
+                reg.set(&self.name(), value);
+            }
+        }
     }
 
     fn set_float(&self, value: f64) {