[ML] Data Frame Analytics Trained models flyout: update horizontal steps size (#167095)

## Summary

Related issue: https://github.com/elastic/kibana/issues/162831

- uses small size for EuiStepsHorizontal component

<img width="1354" alt="image"
src="cfe55fce-2fdf-4b6f-ac91-291c96c7c54c">



### Checklist

Delete any items that are not applicable to this PR.

- [ ] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [ ] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard accessibility](https://webaim.org/techniques/keyboard/))
- [ ] Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [ ] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))
- [ ] This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/ml/public/application/components/ml_inference/components/add_inference_pipeline_horizontal_steps.tsx

@@ -113,6 +113,6 @@ export const AddInferencePipelineHorizontalSteps: FC<Props> = memo(
         navSteps[4].status = 'current';
         break;
     }
-    return <EuiStepsHorizontal steps={navSteps} />;
+    return <EuiStepsHorizontal steps={navSteps} size="s" />;
   }
 );