Implicitly use EIP-7702 if authorizationList is given and non-empty (#4961).

Author: ricmoo

src.ts/providers/abstract-signer.ts

@@ -151,7 +151,11 @@ export abstract class AbstractSigner<P extends null | Provider = null | Provider
                     // The network supports EIP-1559!
 
                     // Upgrade transaction from null to eip-1559
-                    pop.type = 2;
+                    if (pop.authorizationList && pop.authorizationList.length) {
+                        pop.type = 4;
+                    } else {
+                        pop.type = 2;
+                    }
 
                     if (pop.gasPrice != null) {
                         // Using legacy gasPrice property on an eip-1559 network,

src.ts/transaction/transaction.ts

@@ -1191,7 +1191,9 @@ export class Transaction implements TransactionLike<string> {
             types.push(this.type);
 
         } else {
-            if (hasFee) {
+            if (this.authorizationList && this.authorizationList.length) {
+                types.push(4);
+            } else if (hasFee) {
                 types.push(2);
             } else if (hasGasPrice) {
                 types.push(1);