Function upload

packages/browser/src/client/tester/context.ts:90–92

(element, files: string | string[] | File | File[], options)

      return convertToLocator(element).unhover(options)
    },
    upload(element, files: string | string[] | File | File[], options) {
      return convertToLocator(element).upload(files, options)
    },

    // non userEvent events, but still useful
    fill(element, text, options) {