Also update download-artifact action to v4 per pending EOL of v3

Author: petetronic

.github/actions/smoke-tests/action.yml

@@ -43,7 +43,7 @@ runs:
 
     # Bits from the VSIX are reused by smokeTest.ts to speed things up.
     - name: Download VSIX
-      uses: actions/download-artifact@v3
+      uses: actions/download-artifact@v4
       with:
         name: ${{ inputs.artifact_name }}