Better pass kwargs

this is not py2 anymore

(cherry picked from commit 6b2766e668)

game/scripts/interface/color_picker.rpy

@@ -428,9 +428,7 @@ init -1 python:
     class SVGradientButton(ImageButton):
 
         def __init__(self, on_click, idle_image, *args, **kwargs):
-            kwargs['sensitive'] = True
-            kwargs['action'] = NullAction()
-            super(SVGradientButton, self).__init__(idle_image, *args, **kwargs)
+            super(SVGradientButton, self).__init__(idle_image, *args, sensitive=True, action=NullAction(), **kwargs)
             self.width = 0
             self.height = 0
             self.on_click = on_click