test: migrate from jest to vitest

[brantphoto]

POC of moving from jest to vitest.

Description

Will update this to list everything changed. Summary is all tests pass. Coverage fails on a few tests but same in jest.

Changes

See individual Github comments. Overall, not so bad. The migration guide was honest, and the trickiest thing to figure out was mocks. After a simple adjustment to mock factories in this code (and how imports worked).

PS I'll need some advice in terms of CI integration.