refactor: Upgrade to Prettier 3 (no-changelog) (#6947)

Supersedes https://github.com/n8n-io/n8n/pull/6937

Excluding fixtures and test workflow JSONs to avoid having to update
tests.

.github/workflows/check-issue-template.yml

@@ -13,6 +13,3 @@ jobs:
         uses: n8n-io/GH-actions-playground@v1
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
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