Resolve the TypeORM readiness check race condition when using `slow-server`

[andrew-farries]

There is a race condition when slow-server starts where the database is considered ready by the waiter init container, but TypeORM has not yet finished initalization. This makes slow-server unusable and the only solution is to restart the slow-server pods.

See internal discussion here and here.

[geropl]

For validation: one symptom were regular error messages on every rollout. Those should be gone with the PR. 👆

[geropl]

Validated that the new rollout did not trigger any errors: https://cloudlogging.app.goo.gl/RoFYTQoU6bSg1WfC7