fix(networkInterface): make sure to check networkInterface is defined

This is one of the potential bugs, at least, one of the customers has already reported. The test coverage is going to be added later in different Pull Request.

Semver: patch

fix(lint): fix linting issues

index.js

@@ -277,8 +277,10 @@ if ((os.platform() === 'win32' && require('is-administrator')()) || process.getu
                 interface.address.startsWith('192.168.'));
         })[0];
 
-        if (networkInterface.mac) { config.mac = networkInterface.mac; }
-        if (networkInterface.address) { config.ip = networkInterface.address; }
+        if (networkInterface) {
+            if (networkInterface.mac) { config.mac = networkInterface.mac; }
+            if (networkInterface.address) { config.ip = networkInterface.address; }
+        }
 
         utils.log(`${config.package} started on ${config.hostname} (${config.ip})`);
         if (config.platform && config.platform.startsWith('k8s')) { k8s.init(); }