[Issue] Update-Engines overwrites the files on 2nd run

[christophvw]

Describe the issue
Update-Engines.ps1 script version 23.11.21.1852 overwrites microsoft_fullpkg.cab when it already exists.

Expected behavior
Do not overwrite valid files as the download takes >15min.

proposed fix:

lines 595ff

When the file does not exists - or has a size different size: download it again - otherwise not

if (((Test-Path $fullPkgPath) -ne $true) -or ((Get-Item $fullPkgPath).Length -ne $manifest.ManifestFile.Package.FullPackage.Size)) {
	$wc.DownloadFile($fullPkgUrl, $fullPkgPath)

	# Detect if there are any subdirectories
	# needed for this engine
	$subDirCount = $manifest.ManifestFile.Package.Files.Dir.Count

	for ($i=0; $i -lt $subDirCount; $i++) {
		CreatePath ($fullPkgDir + $manifest.ManifestFile.Package.Files.Dir[$i].name)
	}

	ExtractCab $fullPkgPath $fullPkgDir

	# Copy the downloaded manifest to the package directory
	Copy-Item $manifestPath -Destination $fullPkgDir

	Write-Host "Download Complete: " $engine.Name
}
else {
	Write-Host "Engine already up to date: " $engine.Name
}