docs: update case studies to feature usage-aware scan outputs

[sonukapoor]

Following the implementation of the usage-aware dependency scanning feature, the CLI's baseline outputs for our case studies (like Juice Shop) have dramatically improved when using the --usage and --only-used flags.

Tasks:

• Update Juice Shop case study to show the noise reduction (from 19 findings down to 5 actionable ones).
• Re-run and update NestJS and Analog case studies if applicable.
• Make sure to update the 'Before vs After' tables and 'Scan command' outputs to explicitly mention the --only-used workflow.