Update FeedId to null in sbom-scan.json to fix the error: (#1634)

Package FeedId for sbom-scan.json should be null, but was: feeds-builtin

Author: mcasperson

step-templates/sbom-scan.json

@@ -10,7 +10,7 @@
       "Id": "9b495093-0020-4df8-bc44-2fd65ab13943",
       "Name": "application",
       "PackageId": "",
-      "FeedId": "feeds-builtin",
+      "FeedId": null,
       "AcquisitionLocation": "Server",
       "Properties": {
         "Extract": "True",