[v14] refactor: render async by default

[mdjastrzebski]

Summary

Test plan

[codecov]

Codecov Report

❌ Patch coverage is 96.22642% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.25%. Comparing base (f534aa7) to head (c4c0d11).
⚠️ Report is 1 commits behind head on v14.

Files with missing lines	Patch %	Lines
src/unsafe-render-sync.tsx	92.15%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              v14    #1846      +/-   ##
==========================================
+ Coverage   91.05%   91.25%   +0.20%     
==========================================
  Files          94       94              
  Lines        5453     5445       -8     
  Branches      592      907     +315     
==========================================
+ Hits         4965     4969       +4     
+ Misses        483      471      -12     
  Partials        5        5              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.