fix(loadbalance): prevent panic in consistent hash toKey for non-string args (#3430)

The hard type assertion args[i].(string) panics for any non-string
argument (int, struct, etc.), while Java Dubbo uses toString() which
never fails. Replace with fmt.Fprint(&sb, args[i]) which safely
converts any type to its string representation.

Author: Aias00

cluster/loadbalance/consistenthashing/selector.go

@@ -85,7 +85,7 @@ func (c *selector) toKey(args []any) string {
 	var sb strings.Builder
 	for i := range c.argumentIndex {
 		if i >= 0 && i < len(args) {
-			_, _ = fmt.Fprint(&sb, args[i].(string))
+			_, _ = fmt.Fprint(&sb, args[i])
 		}
 	}
 	return sb.String()