message: fix(text): assume default stroke blend with a dark background when dark mode.
  Fix wrong border color when set dark mode manually without backgroundColor
diff: @@ -684,10 +684,11 @@ class Element<Props extends ElementProps = ElementProps> {
  if (!colorArr) {
  colorArr = [255, 255, 255, 1];
  }
  - // Assume blending on a white background.
  + // Assume blending on a white / black(dark) background.
  const alpha = colorArr[3];
  + const isDark = this.__zr.isDarkMode();
  for (let i = 0; i < 3; i++) {
  - colorArr[i] = colorArr[i] * alpha + 255 * (1 - alpha);
  + colorArr[i] = colorArr[i] * alpha + (isDark ? 0 : 255) * (1 - alpha);
  }
  colorArr[3] = 1;
  return stringify(colorArr, 'rgba');
  