fix(ci): Add -Force to Expand-Archive for Flutter GUI

The installer directory already has files from the copy step, so
Expand-Archive needs -Force to overwrite/merge.

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -75,7 +75,7 @@ jobs:
       run: ls
       working-directory: ./windows
     - name: Unzip Flutter GUI
-      run: Expand-Archive -Path ./windows.zip -DestinationPath ./installer
+      run: Expand-Archive -Path ./windows.zip -DestinationPath ./installer -Force
       working-directory: ./windows
     - name: Display installer folder contents
       run: Get-ChildItem -Recurse ./installer