Don't set location restriction based on last user to update filters
Don't set location restriction based on last user to update filters

Now, when an export is created, its location restrictions are fixed.
Users can still add more restrictive location filters, but never
more permissive. This prevents a user with less restrictions from
"taking away" an export that was created by a user with more
restrictive location permissions.

dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq