Roll engine 96ad0c8926b0..a1dcb2ea987e (6 commits) (#29658)

https://github.com/flutter/engine/compare/96ad0c8926b0...a1dcb2ea987e

git log 96ad0c8926b0493d4276a39ee9bc6de6fa97bece..a1dcb2ea987efe0e257832160a1b0583ac219584 --no-merges --oneline
a1dcb2ea9 [ios] Set contentsScale before we commit CATransaction (flutter/engine#8218)
fa1931f6a Send macOS keyboard data to the engine (flutter/engine#8219)
45f69ac47 Plumb a reference of PlatformViewsController and AccessibilityBridge to each other (flutter/engine#8208)
7cbbdb400 libtxt: more accurate tracking of run positioning and width for justified text (flutter/engine#8214)
172810342 Add a build dependencies script for Linux desktop (flutter/engine#8160)
d764b69b2 Add docs for helpful commands to fix format (flutter/engine#8171)

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bin/internal/engine.version

-96ad0c8926b0493d4276a39ee9bc6de6fa97bece
+a1dcb2ea987efe0e257832160a1b0583ac219584