fix: revert use azcli login for azcopy in windows

[awesomenix]

Reverts #8047

[Copilot]

Pull request overview

This PR reverts the prior change that configured AzCopy to use Azure CLI–based authentication on Windows, restoring MSI-based authentication for AzCopy usage in Windows VHD build and Windows e2e log upload paths.

Changes:

• Windows VHD build: stop setting AzCopy AZCLI auto-login env vars and explicitly run azcopy login with --login-type=MSI.
• Windows e2e log upload: switch AzCopy auto-login to MSI and remove the explicit azcopy login call.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
vhdbuilder/packer/windows/configure-windows-vhd.ps1	Updates AzCopy authentication from AZCLI env-based auto-login to explicit MSI login during VHD build downloads.
e2e/vmss.go	Updates the Windows RunCommand log-upload script to use MSI auto-login environment variables and removes the explicit AzCopy login step.

[Copilot]

azcopy.exe is a native executable, so $ErrorActionPreference = "Stop" will not fail the script when azcopy login/azcopy copy returns a non-zero exit code. As written, a login/copy failure can be silently ignored and the VHD build may proceed with confusing downstream errors. Capture $LASTEXITCODE after these calls (and throw/log AzCopy logs on failure), or wrap them in a helper that enforces failure on non-zero exit codes.

Suggested change

	.\azcopy.exe login --login-type=MSI
	Write-Log "Copying $URL to $Dest"
	.\azcopy.exe copy "$URL" "$Dest"
	.\azcopy.exe login --login-type=MSI
	$azcopyLoginExitCode = $LASTEXITCODE
	if ($azcopyLoginExitCode -ne 0)
	{
	Write-Log "AzCopy login failed with exit code $azcopyLoginExitCode"
	if (Test-Path -Path "$env:AZCOPY_LOG_LOCATION\*.log")
	{
	Write-Log "--- START AzCopy Log (on login failure)"
	Get-Content "$env:AZCOPY_LOG_LOCATION\*.log" | Write-Log
	Write-Log "--- END AzCopy Log (on login failure)"
	}
	throw "AzCopy login failed with exit code $azcopyLoginExitCode"
	}
	Write-Log "Copying $URL to $Dest"
	.\azcopy.exe copy "$URL" "$Dest"
	$azcopyCopyExitCode = $LASTEXITCODE
	if ($azcopyCopyExitCode -ne 0)
	{
	Write-Log "AzCopy copy from $URL to $Dest failed with exit code $azcopyCopyExitCode"
	if (Test-Path -Path "$env:AZCOPY_LOG_LOCATION\*.log")
	{
	Write-Log "--- START AzCopy Log (on copy failure)"
	Get-Content "$env:AZCOPY_LOG_LOCATION\*.log" | Write-Log
	Write-Log "--- END AzCopy Log (on copy failure)"
	}
	throw "AzCopy copy failed with exit code $azcopyCopyExitCode"
	}

[Copilot]

The RunCommand PowerShell script relies on azcopy.exe copy succeeding, but native exe failures won’t automatically stop the script unless you explicitly check $LASTEXITCODE/throw (or set up error handling that converts non-zero exit codes into terminating errors). Without that, log uploads can partially fail while the run command still returns success, making debugging flaky. Consider adding explicit exit-code checks after each AzCopy invocation so the test fails fast when uploads fail.