block.json config

{
  "name": "acf/icon",
  "title": "Icon",
  "description": "A custom acf block for icons.",
  "style": ["file:./icon.css"],
  "category": "formatting",
  "icon": "star-empty",
  "keywords": ["icon"],
  "acf": {
    "mode": "edit",
    "renderTemplate": "blocks/icon/icon.php"
  },
  "supports": {
    "anchor": true,
    "align": ["left", "center", "right", "wide", "full"],
    "color": {
      "background": true,
      "text": false,
      "gradients": false
    }
    
  }
}

  "supports": {
    "fullHeight": true,
  }
// check if $block['full_height'] is set then add class
if ( isset($block['full_height']) && true === $block['full_height'] ) {
    $blockClasses .= ' full-height';
}