[CI] prefer chocolatey's nsis

extra/azure-pipelines/build-windows.yml

@@ -30,6 +30,8 @@ jobs:
           choco install --no-progress nsis.portable --version 3.02 -y
           choco install --no-progress curl wget 7zip.portable -y
         displayName: Install dependencies
+      - powershell: Write-Host "##vso[task.prependpath]C:\ProgramData\chocolatey\bin"
+        displayName: Prepend Chocolatey path
       - template: install-neko-snapshot.yaml
         parameters:
           ${{ if eq(parameters.arch, '64') }}: