series without a stroke cause bugs in point rendering and hover points

pretty surprising that this has never come up.

the logic for setting default point fills and stokes is actually quite complicated, given that it has to account for various combos of missing settings, and that point fills come from series strokes unless explicitly defined otherwise.

you can still get it working by being explicit. it's just the defaults/fallbacks that are not working.

series: [
  {},
  {
    // stroke: "red",
    fill: "rgba(255,0,0,0.1)",
    value: fmtVal,
    points: {
      stroke: "red",
    }
  },
  {
    // stroke: "green",
    fill: "rgba(0,255,0,0.1)",
    value: fmtVal,
    points: {
      stroke: "green",
    }
  },
  {
    // stroke: "blue",
    fill: "rgba(0,0,255,0.1)",
    value: fmtVal,
    points: {
      stroke: "blue",
    }
  },
],

Reproduce the issue with the provided series configuration, then trace the JavaScript logic that supplies default and fallback values for series stroke, fill, and point stroke. Check both point rendering and hover points when series strokes are omitted, and verify the behavior against the explicit-stroke example.