Switch to built-in Audit diagnostic setting policy

[SenthuranSivananthan]

Overview/Summary

We are switching to a built-in Azure Policy to audit for diagnostic settings. This policy was previously created as a custom policy so that we only monitor for logs (instead of logs & metrics).

Azure Policy team has updated the built-in policy to provide the ability toggle which type of data that needs to be monitored through the policy. As a result, we are now able to remove the custom policy and reference the built-in.

This PR fixes/adds/changes/removes

Fixes #134

Breaking Changes

No breaking change.

Customers will need to manually remove the custom policy definition from Azure once the updated Custom - Log Analytics for Azure Services Policy initiative is deployed. Steps:

1. Launch Azure Portal
2. Navigate to Azure Policy
3. Navigate to Definitions
4. Find policy definition: "Audit diagnostic setting - Logs" and Delete.

Deletion will succeed given it will no longer referenced in any Policy Initiatives (policy sets) in our automation.

Testing Evidence

Custom Audit diagnostic setting policy that's used in the Log Analytics for Azure Services initiative

Replaced with built-in policy

As part of this Pull Request I have

• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated relevant and associated documentation.

[skeeler]

Looks good