I see you already have the commands. You can use the following steps to run your vsTest runner with Percy on Azure pipelines:
Installing the Percy CLI
npm install --save-dev @percy/cli
npm install -g @percy/cli@latest
Next step should be to set your Percy's project token
set PERCY_TOKEN=TOKEN
Then run your vsTest with Percy
npx percy app:exec -- dotnet test path/to/name-of-CSProj.csproj
These are the steps to be added in your Azure pipeline configuration file, I hope after following this you should be able to run your test without any issue. If you still face any issue after that maybe you can reach out to their support team for help.