Fix expected exit code for mono in source-build smoke tests

The mono issue that caused the different exit code was fixed in dotnet/runtime#100056.

We now have the same exit code as coreclr so remove the mono special case.

Fixes dotnet/source-build#3174
Fixes dotnet/source-build#4514

src/SourceBuild/content/test/Microsoft.DotNet.SourceBuild.SmokeTests/DotNetHelper.cs

@@ -216,8 +216,7 @@ public void ExecuteRun(string projectName) =>
 
     public void ExecuteRunWeb(string projectName, DotNetTemplate template)
     {
-        // 'dotnet run' exit code differs between CoreCLR and Mono (https://github.com/dotnet/sdk/issues/30095).
-        int expectedExitCode = IsMonoRuntime ? 143 : 0;
+        int expectedExitCode = 0;
 
         ExecuteWeb(
             projectName,