staking: tweak tracing events (review)

see: #3875 (comment)

crates/core/component/stake/src/component/epoch_handler.rs

@@ -373,6 +373,10 @@ pub trait EpochHandler: StateWriteExt + ConsensusIndexRead {
         // be in the CS index. We should replace the union set approach with a merged
         // stream that tags items with their source. See #3874.
         if !self.belongs_in_index(&validator.identity_key).await {
+            tracing::debug!(
+                validator_id = %validator.identity_key,
+                "removing validator from consensus set"
+            );
             self.remove_consensus_set_index(&validator.identity_key);
         }
 

crates/core/component/stake/src/component/stake.rs

@@ -489,29 +489,27 @@ pub trait ConsensusIndexRead: StateRead {
     }
 
     /// Returns whether the given validator should be indexed in the consensus set.
+    #[instrument(level = "error", skip(self))]
     async fn belongs_in_index(&self, validator_id: &IdentityKey) -> bool {
         let Some(state) = self
             .get_validator_state(validator_id)
             .await
             .expect("no deserialization error")
         else {
-            tracing::error!(
-                %validator_id,
-                "consensus set index check returned false because validator state was not found");
+            tracing::error!("validator state was not found");
             return false;
         };
 
-        let belongs_in_index =
-            matches!(state, validator::State::Active | validator::State::Inactive);
-
-        tracing::debug!(
-            %validator_id,
-            ?belongs_in_index,
-            ?state,
-            "does not belong in consensus set"
-        );
-
-        belongs_in_index
+        match state {
+            validator::State::Active | validator::State::Inactive => {
+                tracing::debug!(?state, "validator belongs in consensus set");
+                true
+            }
+            _ => {
+                tracing::debug!(?state, "validator does not belong in consensus set");
+                false
+            }
+        }
     }
 }