test(e2e): Check the stream's description without asking pixelflux's bindings
test_system_usage checked what the page is told the stream runs on only where an importable pixelflux had ScreenCapture.stream_info. The server links pixelflux and always sends stream_info, so the check runs everywhere and the suite imports nothing of the bindings.
test_system_usage all: 18/18, the stream_info check on both transports.