Reorganize bundle analyzer toolbar (#98920)
## Summary
Split the bundle analyzer toolbar into two rows so route context,
comparison controls, and search remain separate from filtering and view
controls.
Keep the layout usable at narrow viewport widths by wrapping the route
selector and allowing the filter strip to scroll horizontally.
## Verification
- `pnpm --filter @next/bundle-analyzer-ui exec tsc --noEmit`
- `pnpm --filter @next/bundle-analyzer-ui build`
- Checked the analyzer layout at desktop, 900px, and 390px viewport
widths
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Co-authored-by: vercel-fleet-prod[bot] <318278635+vercel-fleet-prod[bot]@users.noreply.github.com>
Co-authored-by: Will Binns-Smith <755844+wbinnssmith@users.noreply.github.com>
