stop logging public keys on signature cache hit

addresses review comment https://github.com/ava-labs/awm-relayer/pull/467/files#r1752146075

signature-aggregator/aggregator/cache/cache.go

@@ -1,7 +1,6 @@
 package cache
 
 import (
-	"encoding/hex"
 	"math"
 
 	"github.com/ava-labs/avalanchego/ids"
@@ -42,15 +41,10 @@ func (c *Cache) Get(msgID ids.ID) (map[PublicKeyBytes]SignatureBytes, bool) {
 	cachedValue, isCached := c.signatures.Get(msgID)
 
 	if isCached {
-		var encodedKeys []string
-		for key := range cachedValue {
-			encodedKeys = append(encodedKeys, hex.EncodeToString(key[:]))
-		}
 		c.logger.Debug(
 			"cache hit",
 			zap.Stringer("msgID", msgID),
 			zap.Int("signatureCount", len(cachedValue)),
-			zap.Strings("public keys", encodedKeys),
 		)
 		return cachedValue, true
 	} else {