feat(arm): add CKV_AZURE_87 to ensure that Azure Defender is set to On for Key Vault

[userrut]

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PR Title

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ex.
feat(terraform): add CKV_AWS_123 to ensure that VPC Endpoint Service is configured for Manual Acceptance

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Description

Add a new policy to ensure that Azure Defender is set to On for Key Vault

Fixes # (issue)

New/Edited policies (Delete if not relevant)

Description

Include a description of what makes it a violation and any relevant external links.

Fix

How does someone fix the issue in code and/or in runtime?

Checklist:

• [X] My code follows the style guidelines of this project
• [X] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [X] I have added tests that prove my feature, policy, or fix is effective and works
• [X] New and existing tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules