Improve help/docs when dotnet-dsrouter can't connect to device with error 61 #24343
Description
Ref: #24323
When dotnet-dsrouter says:
Failed USBMuxConnectByPort: device = 3, port = 9000, result = 61.
It means that either the app isn't running, or it wasn't built with diagnostics support, or the correct environment variables weren't set at startup.
We should improve dotnet-dsrouter's error output to be more actionable.