PreferPageRenderingUpdatesNear60FPSEnabled got move to `unstable` in 260420@main
<rdar://106209226>
Pull request: https://github.com/WebKit/WebKit/pull/14794
Committed 265027@main (0f5a3fe6bf2e): <https://commits.webkit.org/265027@main> Reviewed commits have been landed. Closing PR #14794 and removing active labels.