Migrations and model snapshot for primitive collections

[ajcvickers]

[bricelam]

Double-check complex type coverage too

[bricelam]

From #31630 (comment)

check that we're not putting user CLR types in migrations for primitive collections (or complex types)

[bricelam]

Not seeing any issues with primitive collections. They really are just strings to migrations and the snapshot. I'll double-check that we have automated tests before closing.

Seeing a few issues with complex types. I'll keep testing and file separate issues.