allow user to override instance and attachments directly
allow user to override instance and attachments directly

if overridden, spoofing a request no longer required

SEL-Columbia/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,qedsoftware/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,SEL-Columbia/commcare-hq,qedsoftware/commcare-hq,puttarajubr/commcare-hq,SEL-Columbia/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,qedsoftware/commcare-hq,qedsoftware/commcare-hq