Setting preference 'OverrideUserAgent' that usually goes in config.xml

I’m trying to add google oauth via webview and google oauth service requires that I set the preference <preference name="OverrideUserAgent" value="Mozilla/5.0 Google" /> that goes in the config.xml.
How and where can I set this preference in fusetools project?

Thanks in advance

Tried this … but no luck

fusepm install https://github.com/bolav/fuse-usersettings

in UX

In JS
var settings = require(‘UserSettings’);
settings.setString(‘OverrideUserAgent’, ‘Mozilla/5.0 Google’);

Still <preference name="OverrideUserAgent" value="Mozilla/5.0 Google" /> is not set, so Google webview oauth says disallowed_useragent - as it is classified as embedded user-agent