feat(net): add reported bad transactions metric (#2270)

crates/net/network/src/metrics.rs

@@ -40,6 +40,8 @@ pub struct NetworkMetrics {
 pub struct TransactionsManagerMetrics {
     /// Total number of propagated transactions
     pub(crate) propagated_transactions: Counter,
+    /// Total number of reported bad transactions
+    pub(crate) reported_bad_transactions: Counter,
 }
 
 /// Metrics for Disconnection types

crates/net/network/src/transactions.rs

@@ -534,6 +534,7 @@ where
                     if err.is_bad_transaction() && !this.network.is_syncing() {
                         trace!(target: "net::tx", ?err, "Bad transaction import");
                         this.on_bad_import(*err.hash());
+                        this.metrics.reported_bad_transactions.increment(1);
                         continue
                     }
                     this.on_good_import(*err.hash());