Fix scatter3d opacity restyle bug

[dwoznicki]

This is a fix for #5957. I've modified the scatter3d attributes to make opacity trigger a full layout replot when the opacity is changed via Plotly.restyle. Note that this solution is derived from the scattergl trace (https://github.com/plotly/plotly.js/blob/master/src/traces/scattergl/attributes.js), which handles opacity changes correctly.

[archmoj]

Thanks for the PR.
It appears the schema needs an update.
Please run the following after npm start.

npm run schema && \ 
git add test/plot-schema.json && \
git commit -m "update plot-schema diff"

[archmoj]

The fix looks great.

1. Please add a test in the interaction section of test/jasmine/tests/scatter3d_test.js for example

Plotly.newPlot(
  gd,
  [
    {
      type: "scatter3d",
      x: [0],
      y: [0],
      z: [0],
      mode: "markers",
    }
  ],
).then(function() {
  Plotly.restyle(gd, 'opacity', 0.5).then(function() {
    expect(gd._fullLayout.scene._scene.glplot.objects[0].hasAlpha).toEqual(true);
  });
});

Also please create draftlog/5958_fix.md file as described here for example

 - Fix scatter3d opacity restyle bug [[#5958](https://github.com/plotly/plotly.js/pull/5958)],
   with thanks to @dwoznicki for the contribution!

[archmoj]

Nicely done.
💃