Merge from public release/6.0.1xx to internal/release/6.0.1xx and resolve conflicts if necessary

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#### AI description  (iteration 1)
#### PR Classification
Code cleanup and script updates.

#### PR Summary
This pull request merges changes from the public repository, focusing on cleaning up and updating post-build scripts.
- Added `nuget-verification.ps1` to verify Microsoft NuGet packages.
- Removed `post-build-utils.ps1`, `trigger-subscriptions.ps1`, and `add-build-to-channel.ps1`.
- Updated `publish-build-assets.yml` to use `AzureCLI@2` instead of `PowerShell@2`.
- Modified `setup-maestro-vars.yml` to use `AzureCLI@2` and updated script logic.
- Updated `publish-using-darc.ps1` to include `--ci` parameter and adjusted token handling.