AdditionalValidationPackagesFromPackageSetFn now accepts all discovered packages (#23466)

Co-authored-by: Scott Beddall <scbedd@microsoft.com>

eng/common/scripts/Package-Properties.ps1

@@ -154,7 +154,7 @@ function Get-PrPkgProperties([string]$InputDiffJson) {
 
     if ($AdditionalValidationPackagesFromPackageSetFn -and (Test-Path "Function:$AdditionalValidationPackagesFromPackageSetFn"))
     {
-        $packagesWithChanges += &$AdditionalValidationPackagesFromPackageSetFn $packagesWithChanges $diff
+        $packagesWithChanges += &$AdditionalValidationPackagesFromPackageSetFn $packagesWithChanges $diff $allPackageProperties
     }
 
     return $packagesWithChanges