Now that the ControlList::get() function returns an std::optional<>, it
is the preferred way to test if a control is present in a ControlList.
Use it in the test to prepare for removal of ControlList::contains().
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>