fix: review comments

Author: zhjwpku

src/iceberg/type_fwd.h

@@ -123,6 +123,9 @@ class Uuid;
 class Expression;
 class Literal;
 
+class BoundPredicate;
+class UnboundPredicate;
+
 class DataTableScan;
 class FileScanTask;
 class ScanTask;
@@ -161,9 +164,6 @@ class PendingUpdate;
 template <typename T>
 class PendingUpdateTyped;
 
-class BoundPredicate;
-class UnboundPredicate;
-
 /// ----------------------------------------------------------------------------
 /// TODO: Forward declarations below are not added yet.
 /// ----------------------------------------------------------------------------