Add ObjectBox to Device Sync deprecation page

[krollins-mdb]

Pull Request Info

Jira ticket: https://jira.mongodb.org/browse/DOCSP-NNNNN

Staging Links

sync/device-sync-deprecation

Reminder Checklist

Before merging your PR, make sure to check a few things.

• Did you tag pages appropriately?
  • genre
  • programming_language
  • meta.keywords
  • meta.description
• Describe your PR's changes in the Release Notes section
• Create a Jira ticket for related docs-realm work, if any

Release Notes

Review Guidelines

REVIEWING.md

[netlify]

✅ Deploy Preview for app-services ready!

Name	Link
🔨 Latest commit	933ddc0
🔍 Latest deploy log	https://app.netlify.com/sites/app-services/deploys/66ed7fba3a159b0008057232
😎 Deploy Preview	https://deploy-preview-853--app-services.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 24 (🔴 down 11 from production) Accessibility: 79 (🔴 down 6 from production) Best Practices: 75 (no change from production) SEO: 77 (no change from production) PWA: - View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify site configuration.