core/menusystem: remove canvas use from menu itself

sonic-boost.love/core/modules/menusystem/parent.lua

@@ -25,10 +25,6 @@ function Menu:new(menusystem, name, x, y, w, h)
   self.sound.asset = nil
   self.sound.active = false
 
-  self.canvas = {}
-  self.canvas.texture     = nil
-  self.canvas.needRedraw  = true
-
   self:register()
 end
 
@@ -78,14 +74,7 @@ function Menu:destroy()
 end
 
 function Menu:draw()
-  if self.canvas.needRedraw == true then
-    core.screen:cease()
-    self:drawCanvas()
-    self.canvas.needRedraw = false
-    core.screen:apply()
-  end
-
-  love.graphics.draw(self.canvas.texture, self.x, self.y)
+  -- nothing here
 end
 
 function Menu:drawCanvas()
@@ -142,7 +131,6 @@ function Menu:moveCursor(new_selected)
       self.widget.selected = new_selected
     end
   end
-  self.canvas.needRedraw = true
 end
 
 function Menu:setSound(soundasset)