[EDR Workflows][Staged rollout] Add artifact channel to Alert flyout's highlighted fields (#208346)

## Summary

This PR adds `Endpoint.policy.applied.artifacts.global.channel` to the
highlighted fields of an alert. This field shows the users, which
artifact channel was used to update the rules on an Endpoint using
Elastic Defend integration.

Based on the structure of the highlighted fields, I think it makes sense
to add it to the 'always displayed fields', but not 100% sure on it, so
I'm happy to take suggestions.

<img width="731" alt="image"
src="https://github.com/user-attachments/assets/952dfc92-e9c4-4b38-8fba-8fc6a5e07ed8"
/>


### Checklist

Check the PR satisfies following conditions. 

Reviewers should verify this PR satisfies this list as well.

- [x] [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

x-pack/solutions/security/plugins/security_solution/public/common/components/event_details/get_alert_summary_rows.tsx

@@ -63,6 +63,7 @@ const alwaysDisplayedFields: EventSummaryField[] = [
   }),
 
   // ** //
+  { id: 'Endpoint.policy.applied.artifacts.global.channel' },
   { id: 'user.name' },
   { id: 'rule.name' },
   { id: 'cloud.provider' },

x-pack/solutions/security/plugins/security_solution/public/detection_engine/rule_exceptions/utils/helpers.test.tsx

@@ -1805,6 +1805,9 @@ describe('Exception helpers', () => {
             label: 'Agent status',
           };
         }),
+        {
+          id: 'Endpoint.policy.applied.artifacts.global.channel',
+        },
         {
           id: 'user.name',
         },