Updated healthcheck command to support TLS configuration. accompanying
env.example sets FLEET_SERVER_TLS=true by default but our default test
in docker-compose.yml tests to http. Causes test to fail.
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**Related issue:** Closes https://github.com/fleetdm/fleet/issues/46927
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## Summary by CodeRabbit
* **Chores**
* Updated service health monitoring to correctly probe the health
endpoint over HTTPS when TLS is enabled, and over HTTP when it is not.
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