Properly use Syncable's `add` for each device type.
Properly use Syncable's `add` for each device type.

brave/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,Allow2CEO/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,brave/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,brave/browser-ios