Bug 1623708 - Remove unused pref. r=snorp

Differential Revision: https://phabricator.services.mozilla.com/D67618

--HG--
extra : moz-landing-system : lando

mobile/android/app/mobile.js

@@ -151,7 +151,6 @@ pref("signon.expireMasterPassword", false);
 pref("signon.debug", false);
 
 /* form helper (scroll to and optionally zoom into editable fields)  */
-pref("formhelper.mode", 2);  // 0 = disabled, 1 = enabled, 2 = dynamic depending on screen size
 pref("formhelper.autozoom", true);
 
 /* find helper */