User should be able to navigate back to cart during checkout in the shopping cart portlet

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.1.X EE, 6.2.X EE, 7.0.0 M3
• Fix Version/s: 7.0.0 M2
• Component/s: Util, Util > Shopping
• Labels:
  • QA-TP
• Story Points: 4
• Fix Priority: 2
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/20528

Steps to reproduce
1. Go to Shopping Cart Portlet and add items to the catalog.
2. Add any item to the cart and checkout.
3. Fill in billing/shipping info and click Continue. You can use this test Credit Card number 4222222222222

actual result: the only option is to click finish.
expected result: the user should have the option of going back to the cart to update the order from the checkout screens.