Handle schema mixed data type

[quangkhoa]

Currently the app does not render schema elements that have mixed data type, e.g.

"customAttributes": {
  "default": [],
  "type": "array",
  "items": {
    "type": "object",
    "required": [
      "key",
      "value"
    ],
    "properties": {
      "key": {
        "type": "string",
        "pattern": "^[a-zA-Z0-9_-]+$"
      },
      "value": {
        "type": [
          "number",
          "integer",
          "string",
          "boolean"
        ]
      }
    },
    "additionalProperties": false
  }
}

The app should be able to render the element, as below