Re-enable sanity tests

The scheduled pipeline for sanity tests has been disabled for years; we should re-enable it.

When I tried to compile and run the sanity tests locally, I had to make some changes to get them to compile.

I encountered two types of errors:

Revoked identity number *** should have a non-null next_scheduled value

This error occurred for 3,519 identities. After investigation, it appears that MR !275 (merged) did not include a migration to populate the next_scheduled field for identities revoked before this change.

Member identity number 61 should have a null next_scheduled value

This error occurred for a single identity. I haven’t determined the exact cause, but I suspect it’s also due to a missing migration, since it’s an old v1 identity.

We should reintroduce these sanity tests using GTest and ensure that we implement proper migrations for every runtime change that affects state.