Previously the function used to upsert into the user dimension required
both an auth token id, and a user id. However, the user id can be
determined from the auth token, in fact it already was via the
whx_user_dimension_source view. This refactor removes the user id as an
argument, since it is not needed and will not be directly available when
this function is used when populating the new auth token accumulating
fact.
Timothy Messier
Johan Brandhorst-Satzkorn
Louis Ruch