`%%py5draw` magic has 2X scaling problem on OSX

[hx2A]

As reported by #710 (comment), the %%py5draw doesn't work correctly on OSX. The following code renders the coordinates correctly on Linux but not OSX:

%%py5draw 300 200

py5.fill("red")
py5.rect_mode(py5.CENTER)
py5.rect(170, 80, 100, 100)

py5.stroke("green")
py5.stroke_weight(15)
py5.line(40, 30, 220, 180)

I suspect this has something to do with https://py5coding.org/reference/sketch_display_density.html and https://py5coding.org/reference/sketch_pixel_density.html.