Revert "ci: pin dart sdk to 3.9.2 for stable formatting"

This reverts commit 4deb4f5.

Author: reez

.github/workflows/ci.yml

@@ -23,8 +23,6 @@ jobs:
 
       - name: Setup Dart
         uses: dart-lang/setup-dart@v1
-        with:
-          sdk: "3.9.2"
 
       - name: Install lipo (macOS)
         if: matrix.os == 'macos-latest'