Fix: re-implement skipped cart page unit tests @W-15110504@

[joeluong-sfcc]

Description

This PR adds back in tests that were skipped due to some updates that broke those tests. There is still a unit test being skipped, remove from cart test, but I couldn't find a good way to make it pass as it consistently timed out for me.

Types of Changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Documentation update
• Breaking change (could cause existing functionality to not work as expected)
• Other changes (non-breaking changes that does not fit any of the above)

Breaking changes include:

• Removing a public function or component or prop
• Adding a required argument to a function
• Changing the data type of a function parameter or return value
• Adding a new peer dependency to package.json

Changes

• (change1)

How to Test-Drive This PR

1. git checkout ju/fix-cart-tests
2. cd packages/template-retail-react-app
3. npm run test 'app/pages/cart/index.test.js --coverage=false'
4. Observe that the unit test passes and there is only 1 skipped test (remove from cart test)

Checklists

General

• Changes are covered by test cases
• CHANGELOG.md updated with a short description of changes (not required for documentation updates)

Accessibility Compliance

You must check off all items in one of the follow two lists:

• There are no changes to UI

or...

• Changes were tested with a Screen Reader (iOS VoiceOver or Android Talkback) and had no issues
• Changes comply with WCAG 2.0 guidelines levels A and AA
• Changes to common UI patterns and interactions comply with WAI-ARIA best practices

Localization

• Changes include a UI text update in the Retail React App (which requires translation)