[AlertSummaryWidget] Fix storybook theme

[maryam-saeidi]

Summary

In this PR, I fixed the issue with not showing the storybook components due to not passing correct props but I didn't find how to pass the theme so the storybook shows the component similar to how we show it in Kibana. In this ticket, we need to pass a theme similar to Kibana to fix the style of the storybook.

Compact

Full size

Command

Command to run storybook locally:

yarn storybook triggers_actions_ui

[elasticmachine]

Pinging @elastic/obs-ux-management-team (Team:obs-ux-management)