Use PendingTransaction interface in block creation classes (#8254)

Signed-off-by: Fabio Di Fabio <fabio.difabio@consensys.net>

datatypes/src/main/java/org/hyperledger/besu/datatypes/PendingTransaction.java

@@ -43,4 +43,18 @@ public interface PendingTransaction {
    * @return timestamp
    */
   long getAddedAt();
+
+  /**
+   * Return the estimated amount memory that this pending transaction occupies
+   *
+   * @return the estimated memory size
+   */
+  int memorySize();
+
+  /**
+   * Formats a string with detailed information about the pending transaction for debug purposes
+   *
+   * @return a string
+   */
+  String toTraceLog();
 }