Revert "[PER-5758] fix canvas-to-image width handling"

[prklm10]

Reverts percy/cli#1995 We already copy those attributes,

for (let { name, value } of canvas.attributes) {
    img.setAttribute(name, value);
  }

So we don't need the below. So previous was good.

if (canvas.style.maxWidth) {
    img.style.maxWidth = canvas.style.maxWidth;
  }