Fix the apple-app-site-association file.

[pixlwave]

It seems the file had an error where details was a single object instead of an array of objects. This PR fixes it to match the documentation: https://developer.apple.com/documentation/bundleresources/applinks

Generated file:

{
  "applinks": {
    "details": [
      {
        "appIDs": [
          "7J4U792NQT.im.vector.app",
          "7J4U792NQT.io.element.elementx",
          "7J4U792NQT.io.element.elementx.nightly",
          "7J4U792NQT.io.element.elementx.pr"
        ],
        "components": [
          {
            "#": "/*",
            "comment": "Only open urls with a fragment, so you can still create links"
          }
        ]
      }
    ]
  }
}