[core] Redact redis password in log

[letaoj]

Why are these changes needed?

This change is needed to prevent redis password been logged in the standard logging. This is a secure vulnerability.

Related issue number

Closes #50266

Checks

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• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
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• Testing Strategy
  • Unit tests
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  • This PR is not tested :(

[pcmoritz]

Thanks for the contribution! I made a small fix and verified it works:

==> ray_client_server.err <==
2025-02-11 14:16:26,814	INFO server.py:900 -- Starting Ray Client server on 127.0.0.1:10001, args Namespace(host='127.0.0.1', port=10001, mode='proxy', address='127.0.0.1:6379', redis_username=None, redis_password='****', runtime_env_agent_address='http://127.0.0.1:60712')

[letaoj]

@pcmoritz ah, I saw you enabled auto merge. Thanks!