Format code with prettier

This commit fixes the style issues introduced in 2db1b6a according to the output
from prettier.

Details: https://deepsource.io/gh/MillenniumEarl/F95API/transform/0f5f4240-51d3-4a7b-b22a-6d2446036acb/

app/index.js

@@ -308,8 +308,7 @@ module.exports.logout = function () {
 
   // Gracefully close shared browser
   if (!shared.isolation && _browser !== null) {
-    _browser.close()
-    .then(() => _browser = null);
+    _browser.close().then(() => (_browser = null));
   }
 };
 //#endregion