feat(sdk-coin-icp): implement combine method for signed transaction generation

TICKET: WIN-4908

Author: mohd-kashif

modules/sdk-coin-icp/src/lib/transactionBuilder.ts

@@ -4,6 +4,7 @@ import { BaseTransactionBuilder, BuildTransactionError, BaseAddress, SigningErro
 import { Transaction } from './transaction';
 import utils from './utils';
 import { IcpTransactionData } from './iface';
+import { SignedTransactionBuilder } from './signedTransactionBuilder';
 
 export abstract class TransactionBuilder extends BaseTransactionBuilder {
   protected _transaction: Transaction;
@@ -144,4 +145,13 @@ export abstract class TransactionBuilder extends BaseTransactionBuilder {
       throw new SigningError('Invalid private key');
     }
   }
+
+  // combine the unsigned transaction with the signature payload and generates the signed transaction
+  protected combine(): void {
+    const signedTransactionBuilder = new SignedTransactionBuilder(
+      this._transaction.unsignedTransaction,
+      this._transaction.signaturePayload
+    );
+    this._transaction.signedTransaction = signedTransactionBuilder.getSignTransaction();
+  }
 }

modules/sdk-coin-icp/src/lib/transferBuilder.ts

@@ -13,7 +13,6 @@ import {
   IcpTransactionData,
   OperationType,
 } from './iface';
-import { SignedTransactionBuilder } from './signedTransactionBuilder';
 import assert from 'assert';
 
 export class TransferBuilder extends TransactionBuilder {
@@ -113,16 +112,6 @@ export class TransferBuilder extends TransactionBuilder {
     this._transaction.icpTransaction = icpTransaction;
   }
 
-  // combine the unsigned transaction with the signature payload and generates the signed transaction
-  protected combine(): BaseTransaction {
-    const signedTransactionBuilder = new SignedTransactionBuilder(
-      this._transaction.unsignedTransaction,
-      this._transaction.signaturePayload
-    );
-    this._transaction.signedTransaction = signedTransactionBuilder.getSignTransaction();
-    return this._transaction;
-  }
-
   /** @inheritdoc */
   protected signImplementation(key: BaseKey): BaseTransaction {
     const signatures = this._utils.getSignatures(this._transaction.payloadsData, this._publicKey, key.key);