Thank you for taking the time to respond to my concerns.
I checked the bin folder for my unit testing project and the xunit.execution.desktop.dll file is in the same folder as the output file for the project.
Per my original post, I also uninstalled XUnit and all of its dependencies because of this post -
Forum PostAlthough this is a drastic move, I think I'm going to create a new unit testing project and install all of the packages from scratch. I have had issues like this before and sometimes, for whatever reason, it becomes the only solution to work.
I will post my findings here.