fix legacy robot edit issue (#15709)
fix legacy robot edit issue (#15709)

fixes #15690, for the legacy robot, update is denied.

Signed-off-by: Wang Yan <63b20dea16c07a874bc9bf767df5575676113cb6@vmware.com>
wy65701436/harbor,wy65701436/harbor,wy65701436/harbor,wy65701436/harbor,wy65701436/harbor,wy65701436/harbor