syncing a capsule fails with ActiveRecord::RecordNotFound Couldn't find SmartProxy with 'id'=2
Due to the recent taxonomy changes when a user is not set.
Fixes #18656 - fix smart proxy sync without user
after 5f606e11cf39719bf62f8b1f3396861b32387905 was merged into foreman
smart proxy with content could not sync because there is no user being set
as we do not need a user to talk to pulp. So now just look up the smart