chore(ci): Only download required build artifacts for Windows

Our Windows CI has a separate build job with the sole purpose of
creating an installer, by joining three different Windows builds:

- Qt5: x86 and x86_64
- Qt6: x86_64

To accomplish that, this job needs to download these build artifacts
from previous jobs.

Until now, we would download all build artifacts, including ones from
unrelated jobs such as Linux and macOS, which doesn't make sense, as
it's wasteful and slow.

Thankfully, version 4.1.0[1] of 'actions/download-artifact' now allows
us to specify which artifacts to download, which is what this commit
does.

[1] https://github.com/actions/download-artifact/releases/tag/v4.1.0

.github/workflows/windows.yml

@@ -169,9 +169,10 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Download build artifacts from previous job
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           path: artifacts
+          pattern: '*Windows*'
 
       - name: Ensure a 64-bit Qt 6 build is present
         run: |