Remove obsolete code

Author: makermelissa

examples/ssd1680_2.13_mono_eink_bonnet.py

@@ -50,12 +50,7 @@
 
 with open("display-ruler.bmp", "rb") as f:
     pic = displayio.OnDiskBitmap(f)
-    # CircuitPython 6 & 7 compatible
-    t = displayio.TileGrid(
-        pic, pixel_shader=getattr(pic, "pixel_shader", displayio.ColorConverter())
-    )
-    # CircuitPython 7 compatible only
-    # t = displayio.TileGrid(pic, pixel_shader=pic.pixel_shader)
+    t = displayio.TileGrid(pic, pixel_shader=pic.pixel_shader)
     g.append(t)
 
     display.show(g)