## Summary
- Disable manual record creation (add button, + header button, add new
row) for **WorkflowRun** and **WorkflowVersion** objects since these are
system-managed and should not be created manually
- Fix vertical centering of the record table empty state placeholder
(regression from `styled(Component)` refactor in #18430 — the wrapper
lost `height: 100%` / `width: 100%`)
## Test plan
- [ ] Navigate to Workflow Runs index page → empty state should show
centered placeholder **without** "Add a Workflow Run" button
- [ ] Navigate to Workflow Versions index page → empty state should show
centered placeholder **without** "Add a Workflow Version" button
- [ ] Navigate to any other object index page (e.g. People, Companies) →
empty state should still show the "Add a ..." button and be centered
- [ ] Verify the + button in the record table header is hidden for
workflow runs/versions
- [ ] Verify the "Add New" row at the bottom of the table is hidden for
workflow runs/versions
