Multi-category sorting misbehaves with missing categories

Originally reported in https://github.com/plotly/plotly.py/issues/1491.

There seems to a multi-category sorting bug that wasn't fixed by #3362.

CodePen: https://codepen.io/jonmmease/pen/VNeEqq?editors=1010

var fig = {
  "data": [
    {
      "name": "Fruits",
      "type": "bar",
      "x": [
        [
          2017,
          2017,
          2017,
          2017,
          2017,
          2017,
          2017,
          2017,
          2018,
          2018,
          2018,
          2018
        ],
        [
          4,
          5,
          6,
          8,
          9,
          10,
          11,
          12,
          1,
          2,
          3,
          4
        ]
      ],
      "y": [
        57246.0,
        1587.0,
        63189.0,
        30680.0,
        26071.0,
        117519.0,
        27519.0,
        42643.0,
        8559.0,
        22355.0,
        59363.0,
        62955.0
      ]
    },
    {
      "name": "Price",
      "type": "scatter",
      "x": [
        [
          2017,
          2017,
          2017,
          2017,
          2017,
          2017,
          2017,
          2017,
          2018,
          2018,
          2018,
          2018
        ],
        [
          4,
          5,
          6,
          8,
          9,
          10,
          11,
          12,
          1,
          2,
          3,
          4
        ]
      ],
      "y": [
        0.22991999,
        0.27284184,
        0.18438336,
        0.24866362,
        0.18280848,
        0.19382398,
        0.17268069,
        0.18802617,
        0.17560463,
        0.13415343,
        0.14773512,
        0.31319196
      ],
      "yaxis": "y2"
    }
  ],
  "layout": {
    "height": 600,
    "showlegend": true,
    "yaxis": {
      "showgrid": true,
      "title": {
        "text": "Fruits volume"
      }
    },
    "yaxis2": {
      "anchor": "x",
      "overlaying": "y",
      "showgrid": false,
      "side": "right",
      "title": {
        "text": "Price per unit"
      }
    }
  }
}

Plotly.newPlot('myDiv', fig, {showSendToCloud: true});

The problem is that in the second multi-category (2018), the 4 is sorted before 1, 2, 3 even though they are specified in ascending sorted order.

As noted in https://github.com/plotly/plotly.py/issues/1491, this seems to happen for categories that are not present in the first multi-category (2017).

Reproduce el comportamiento utilizando el ejemplo de CodePen proporcionado y la configuración de Plotly.newPlot, centrándote en la ordenación de un eje de múltiples categorías cuando una categoría aparece únicamente en el grupo posterior. Compara el orden mostrado con el orden ascendente especificado; se considera completado cuando la segunda categoría múltiple se ordena como 1, 2, 3, 4, preservando el comportamiento observado en el ejemplo.