Bicep Walkthrough - Add generate params to walkthrough

To give our users a glimpse at our best practice end to end scenario or authoring a Bicep file, I believe once #7126 is done and the functionality is decided, we should go ahead and add this into the walkthrough.

It would come before the "Deploy your bicep file" blade most likely.

Review issue #7126 first to understand the generate-params functionality and its decided behavior. Then locate the walkthrough entry containing the "Deploy your bicep file" blade; done means the generate-params step appears before that blade and demonstrates the agreed end-to-end scenario.

Written by the indexing model from the issue text.