Fix snippets workflow for latest preview sdk (#29543)

* Fix snippets workflow for latest preview sdk

* Update build-validation.yml

Author: adegeo

.github/workflows/build-validation.yml

@@ -40,7 +40,7 @@ jobs:
         echo "Downloading dotnet-install.ps1"
         Invoke-WebRequest https://raw.githubusercontent.com/dotnet/install-scripts/master/src/dotnet-install.ps1 -OutFile dotnet-install.ps1
         echo "Installing dotnet version ${{ env.DOTNET_INSTALLER_CHANNEL }}"
-        .\dotnet-install.ps1 -InstallDir "c:\program files\dotnet" -Channel "${{ env.DOTNET_INSTALLER_CHANNEL }}"
+        .\dotnet-install.ps1 -InstallDir "c:\program files\dotnet" -Channel "${{ env.DOTNET_INSTALLER_CHANNEL }}" -Quality preview
 
     # Print dotnet info
     - name: Display .NET info