* default to source_query.include_imported before true

This fixes a bug where a Stats API aggregate query was trying
to query current period *without imported data* but previous
period *with imported data*.

* remove __internal_visits at a better time

As soon as we have made the db query, we don't need it anymore

* disallow events metric with imported data

* update changelog

* keep default in a better place

* remove unused option

* update test description

Co-authored-by: Vini Brasil <vini@hey.com>

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Co-authored-by: Vini Brasil <vini@hey.com>