CodeQL should scan C# (dotnet app)

[ctlong]

tldr; CodeQL scanning should include the C# code in assets/dotnet_simple.

When I setup the CodeQL scan for the first time it failed with the following error:

Error: Could not auto-detect a suitable build method
  Error: We were unable to automatically build your code. Please replace the call to the autobuild action with your custom build steps.  Failure invoking /opt/hostedtoolcache/CodeQL/0.0.0-20220623/x64/codeql/csharp/tools/autobuild.sh with arguments .

I'm not sure what the build steps are to get this scan working, so I decided to make an issue and come back to it later. In the meantime, I've updated the scan to not include C#.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/182833363

The labels on this github issue will be updated when the story is started.