fix power automate opensearch integration

[jertel]

Description

Corrects an Opensearch integration mistake with the new Microst Power Automate alerter.

Checklist

• I have reviewed the contributing guidelines.
• I have included unit tests for my changes or additions.
• I have successfully run make test-docker with my changes.
• I have manually tested all relevant modes of the change in this PR.
• [N/A] I have updated the documentation.
• I have updated the changelog.

Questions or Comments

[marssilva]

Hello @jertel

Thanks for the adjustment. All that was missing was the documentation.

`
ms_power_automate_opensearch_discover_color: By default, the alert will be published with the ``default`` type blue if not specified. If set to ``positive``, action is displayed with a positive style (typically the button becomes accent color), If set to ``destructive``, Action is displayed with a destructive style (typically the button becomes red)

`