Update keyring.mock.ts

Co-authored-by: Mark Stacey <markjstacey@gmail.com>

Author: mikesposito

src/test/keyring.mock.ts

@@ -87,7 +87,7 @@ export class KeyringMockWithSignTransaction extends BaseKeyringMock {
     super(options);
   }
 
-  async signTransaction(_from: any, _txData: any, _opts: any): Promise<TxData> {
-    return Promise.resolve(_txData);
+  async signTransaction(_from: any, txData: any, _opts: any): Promise<TxData> {
+    return Promise.resolve(txData);
   }
 }