fix: Add additional permissions for bicep deployment permissions

[oZakari]

Overview/Summary

Fixes #188

This PR fixes/adds/changes/removes

1. Adds "Microsoft.Insights/diagnosticSettings/write" to mgmt group contributor
2. Adds "Microsoft.Authorization/policyAssignments/write" to mgmt group contributor

Breaking Changes

1.None

Testing Evidence

Please provide any testing evidence to show that your Pull Request works/fixes as described and planned (include screenshots, if appropriate).

As part of this Pull Request I have

• Checked for duplicate Pull Requests
• Associated it with relevant issues, for tracking and closure.
• 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.

[jaredfholgate]

LGTM