#7315 improvement(ui): move secret visibility below description

Summary

• move secret visibility below the description field
• preserve existing visibility behavior and styling

Type of Change

• Improvement

Testing

• bun run lint:check
• bun run lint
• bun run apps/sim/scripts/check-block-registry.ts origin/staging
• bun run check:audits

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)