Add `health_check_config` to EndpointRow and synchronize with Appproxy DB

## Motivation

- When selecting a custom runtime variant, health-check parameters can be specified in `model-definition.yml`.
However, for all other runtime variants, there is no way to modify `health_check_config`.
This is a significant issue, especially because `initial_delay` cannot be adjusted, causing some customers’ model services to fail to start inference sessions properly.

JIRA Issue: BA-3288