[8.x] [ci] enable Scout reporter for on-merge-unsupported-ftrs (#210627…

…) (#210672)

# Backport

This will backport the following commits from `main` to `8.x`:
- [[ci] enable Scout reporter for on-merge-unsupported-ftrs
(#210627)](#210627)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Dzmitry
Lemechko","email":"dzmitry.lemechko@elastic.co"},"sourceCommit":{"committedDate":"2025-02-11T18:01:54Z","message":"[ci]
enable Scout reporter for on-merge-unsupported-ftrs (#210627)\n\n##
Summary\r\n\r\nIn #210425 we added Scout UI tests to be run for on-merge
pipeline, but\r\ntest results are not ingested by default.\r\n\r\nThis
PR enables Scout reporter for that
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enable Scout reporter for
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enable Scout reporter for on-merge-unsupported-ftrs (#210627)\n\n##
Summary\r\n\r\nIn #210425 we added Scout UI tests to be run for on-merge
pipeline, but\r\ntest results are not ingested by default.\r\n\r\nThis
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enable Scout reporter for on-merge-unsupported-ftrs (#210627)\n\n##
Summary\r\n\r\nIn #210425 we added Scout UI tests to be run for on-merge
pipeline, but\r\ntest results are not ingested by default.\r\n\r\nThis
PR enables Scout reporter for that
pipeline","sha":"48992ed9f6b78201884b28e1aa77794ea1e61336"}},{"branch":"8.x","label":"v8.19.0","branchLabelMappingKey":"^v8.19.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Dzmitry Lemechko <dzmitry.lemechko@elastic.co>

.buildkite/pipeline-resource-definitions/kibana-on-merge-unsupported-ftrs.yml

@@ -21,6 +21,7 @@ spec:
       env:
         SLACK_NOTIFICATIONS_CHANNEL: '#kibana-unsupported-ftrs-alerts'
         ELASTIC_SLACK_NOTIFICATIONS_ENABLED: 'true'
+        SCOUT_REPORTER_ENABLED: 'true'
       allow_rebuilds: true
       branch_configuration: main 8.15 7.17
       default_branch: main