kwargs are not handled by python D-Bus (i.e. they are not sent through D-Bus). The "profile" and "profile_key" kwargs are often used through SàT with the bridge, this was working so far because they were used for core methods (which have a signature in DBus.py handling profile), or in Libervia browser who ignore profile argument.
But if the profile or profile_key was used as a keyword for plugin method outside of Libervia browser, they were ignored, this commit fix this by adding them to the args list.
e7d024784e