Remove aria-label from images if alt text is not present

[swashbuck]

Subject of the enhancement

If alt text is not present for an image, it is hidden from screen readers with aria-hidden="true". However, the aria-label attribute is still present and serves no purpose.

I would suggest that we completely remove aria-label="" when there is no alt text.

Your environment

• Core 6.53.6

Steps to reproduce

Add a Graphic component with an empty string for the alt text.

  {
    "_id": "c-105",
    "_parentId": "b-100",
    "_type": "component",
    "_component": "graphic",
    "_classes": "",
    "_layout": "right",
    "title": "c-105",
    "displayTitle": "",
    "body": "",
    "instruction": "",
    "_graphic": {
      "alt": "",
      "longdescription": "",
      "large": "course/en/images/single-width.png",
      "small": "course/en/images/single-width.png",
      "attribution": "",
      "_url": "https://kineo.com",
      "_target": ""
    },
    "_isScrollable": false,
    "_defaultScrollPercent": 0,
    "_isOptional": true
  },