ImageField props conflict with API spec

[Mosnar]

https://github.com/agility/agility-next/blob/796142a1b0dbe9a4e85e1d88996f13b3442e51ac/src/types.ts#L209C1-L216C2

The type definition for ImageField has all non-nullable properties; however, if I inspect the data returned from the API, I get:

"myImageField": {
    "label": null,
    "url": "url here",
    "target": null,
    "filesize": 396122,
    "pixelHeight": "304",
    "pixelWidth": "650",
    "height": 304,
    "width": 650
},

A more compliant type would look like this:

export interface ImageField {
  label: string | null;
  url: string;
  target: string | null;
  filesize: number;
  pixelHeight: string;
  pixelWidth: string;
  height: number;
  width: number;
}

This change should be backwards-compatible with AgilityPic