tweaks during transform package updates

[fivetran-jamie]

Are you a current Fivetran customer?

fivetran made PR

What change(s) does this PR introduce?

• adds source_relation to the new staging model test grains (realized this when working in the transform package)
• lowercases emails from the get-go

Did you update the CHANGELOG?

• [ ] Yes
• [X] no

Does this PR introduce a breaking change?

• [ ] Yes (please provide breaking change details below.)
• [X] No (please provide an explanation as to how the change is non-breaking below.)

Did you update the dbt_project.yml files with the version upgrade (please leverage standard semantic versioning)? (In both your main project and integration_tests)

• [ ] Yes
• [x] no this is done in the base

Is this PR in response to a previously created Bug or Feature Request

• [ ] Yes, Issue/Feature [link bug/feature number here]
• [x] No

How did you test the PR changes?

• [x] Buildkite
• [ ] Local (please provide additional testing details below)

Select which warehouse(s) were used to test the PR

• [x] BigQuery
• [x] Redshift
• [x] Snowflake
• [x] Postgres
• [x] Databricks
• [ ] Other (provide details below)

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[fivetran-jamie]

thinking this should not be merged until transform package model work is basically done

[fivetran-jamie]

actually now that this branch has quite a bit of stuff in it, i think it would be best to review/merge this in now (and likely later as well in another PR, i just think splitting it up will be ideal) @fivetran-joemarkiewicz