Add default .NET install path for SDK validation (#25017)

.pipelines/templates/release-validate-sdk.yml

@@ -87,7 +87,16 @@ jobs:
         Get-Content $nugetPath
 
         # Add workaround to unblock xUnit testing see issue: https://github.com/dotnet/sdk/issues/26462
-        $dotnetPath = if ($IsWindows) { "$env:LocalAppData\Microsoft\dotnet" } else { "$env:HOME/.dotnet" }
+
+        $possibleDotnetLocation = "$env:ProgramFiles\dotnet"
+        
+        $dotnetPath = if ($IsWindows) { 
+          if (Test-Path $possibleDotnetLocation) { $possibleDotnetLocation } else { "$env:LocalAppData\Microsoft\dotnet" }
+        }
+        else {
+          "$env:HOME/.dotnet" 
+        }
+
         $env:DOTNET_ROOT = $dotnetPath
 
         dotnet --info