CEXT-4251: Update examples with customer data and product attributes

[oshmyheliuk]

Description

Added examples of using product attributes and customer data in the request payload for shipping methods.

https://jira.corp.adobe.com/browse/CEXT-4251

How Has This Been Tested?

On Commerce Cloud plus AppBuilder

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.