Document uploader as change property
Document uploader as change property

Signed-off-by: Edwin Kempin <d43fb6c98c97e553b671ed9a9318100f1de386e7@google.com>
Bug: Google b/233384278
Release-Notes: skip
Change-Id: Iad4be9d4b9efb912e023f4b639a7f40adb60ff00

GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit