fix(nextwork): airport response is multi-line if wifi disabled

[jakereps]

If WiFi is fully disabled (toggled off on macOS), the response from the networksetup call, while determining if you're on an airport network, fails to be correctly compared due to an additional line of text added.

› networksetup -getairportnetwork en0 | cut -d ':' -f 2
You are not associated with an AirPort network.
Wi-Fi power is currently off.

This results in the network widget displaying the long string "Wi-Fi power is currently off."

This change simply sets it to always grab the first line instead.

› networksetup -getairportnetwork en0 | cut -d ':' -f 2 | head -n 1
You are not associated with an AirPort network.

Which resulted in the correct display of showing my laptop was on Ethernet.

[ethancedwards8]

Good catch. Thanks.