[8.11] chore(NA): use a n2-8-spot instance to build storybooks on prs…

… as well (#168154) (#168216)

# Backport

This will backport the following commits from `main` to `8.11`:
- [chore(NA): use a n2-8-spot instance to build storybooks on prs as
well (#168154)](#168154)

<!--- Backport version: 8.9.7 -->

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

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Co-authored-by: Tiago Costa <[email protected]>

.buildkite/pipelines/pull_request/storybooks.yml

@@ -2,6 +2,6 @@ steps:
   - command: .buildkite/scripts/steps/storybooks/build_and_upload.sh
     label: 'Build Storybooks'
     agents:
-      queue: n2-4-spot
+      queue: n2-8-spot
     key: storybooks
     timeout_in_minutes: 60