Custom content type not applied to ssr sites

[klaemo]

Custom assets.fileOptions[].contentType values are not applied to the matched files.

{
  async run() {
    new sst.aws.Remix("Frontend", {
      assets: {
        fileOptions: [
          {
            files: "**/*.webmanifest",
            contentType: "application/manifest+json", // <- not applied
          },
          {
            files: ["assets/**/*.css", "assets/**/*.js"],
            cacheControl: "public,max-age=31536000,immutable",
          },
        ],
      },
    })
  },
}

[klaemo]

Corresponding PR: sst/ion#722