Don't run ExampleTester unit tests since it's covered in a different run

Author: jnm2

.github/workflows/tools-tests.yaml

@@ -31,6 +31,7 @@ jobs:
         dotnet-version: 8.0.x
 
     - name: Run all tests
+      # Avoiding running unit tests for ExampleTester which is covered in a different run.
       run: |
         cd tools
-        dotnet test
+        dotnet test MarkdownConverter.Tests