[FEAT] Reflect unhealthy providers in application status

[brooksmtownsend]

The Provider spreadscaler + daemonscalers currently handle provider_start_failed events to update application status based on application level events. We should extend this handling to also include health_check_failed events and health_check_succeeded in order to reflect when an application is unhealthy.

We could start this feature using the existing Failed status to reflect the issue, but we may want to add an Unhealthy status to indicate that the application was scheduled/deployed but with problems.

See https://wasmcloud.com/docs/reference/cloud-event-list#health_check_passed for the event specifications.