Remove Plaid from tests

[tmyracle]

This has ended up being more involved than I would have liked. Spent a good chunk of time trying to figure out why a test wasn't passing and finally realized there was a database function that was doing some calculations that wasn't apparent from the codebase 😑

Not ready yet, got 2 more tests to replace Plaid in but wanted to show some progress for @MichaelDeBoey 😄