[8.1] define configuration to expose to the browser (#128938)

[kibanamachine]

Backport

This will backport the following commits from main to 8.1:

• define configuration to expose to the browser (#128938)

Questions ?

Please refer to the Backport tool documentation

[kibana-ci]

💚 Build Succeeded

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• Commit: 335d05c
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Metrics [docs]

✅ unchanged

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @klacabane