Use correct slot when querying gene aggregations

[naglepuff]

Breaking Changes

This PR includes changes to ingest. Until upstream data is migrated to include the schema changes that necessitated this change, ingest will fail to create records based on functional_annotation_aggs

Summary of changes

The slot that links functional_annotation_agg members to their workflow_executions has been changed to be was_generated_by. This change is now reflected in ingest code.

To test

Make sure ingest populates the ____GeneFunctionAggregation tables.

[naglepuff]

@marySalvi this is ready for review, now that dev mongo has been migrated