Fix Amber vaidation and resource example handling in Examples Command

[StarKhan6368]

What: Fix Amber validation and resource example handling in Examples Command

Why:

• Exit code depends on amber validation.
• Resource examples are validated, and skipped if found to be empty
• Warnings count for amber validation failures

Checklist:

• Documentation added to the README.md OR link to PR on https://github.com/specmatic/specmatic-documentation
• Tests
• Sonar Quality Gate

Issue ID:
Closes: #123