fix(amazonq): validate yaml file for required keys

[dhasani23]

Problem

Sometimes a .yaml file QCT asks for from the customer is malformed and users don't see what exactly is wrong.

Solution

Validate the file and provide a more specific error message.

---

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[amazon-inspector-ohio]

⏳ I'm reviewing this pull request for security vulnerabilities and code quality issues. I'll provide an update when I'm done

[github-actions]

• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.

[amazon-inspector-ohio]

✅ I finished the code review, and didn't find any security or code quality issues.

[ntarakad-aws]

Do we need changelog for this fix?