Explore more predictable solutions for `previous_*` field values

[fivetran-jamie]

In pendo__page_event and pendo__feature_event, we have the following kind of logic for grabbing previous page/feature event values:

lag(<field>) over(partition by visitor_id order by occurred_at asc, _fivetran_synced asc) as previous_<field>

However, events will often have identical occurred_at and _fivetran_synced timestamps, so SQL arbitrarily chooses the previous event.

Let's explore other solutions to produce consistent outputs -- perhaps there have been new fields added since we first made these models that we can leverage.