Draft: Update health_check.md

What does this MR do?

The current documentation does not mention the use of health access tokens for the monitoring endpoints.

# needs token for remote monitoring
/-/readiness
/-/liveness

# does not need token for remote monitoring
/-/health

If you are just using them locally, then you don't need to use the tokens however if you are going to monitor the endpoints remotely then you will need to use the tokens along with the whitelist (with exception of /-/health).

Related issues

!114815 (merged) 18521584

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