uploads: include media assets in API response.

Include media assets in /uploads.json and /uploads/:id.json API responses, like this:

    {
      "id": 4983629,
      "source": "https://www.pixiv.net/en/artworks/96198438",
      "uploader_id": 52664,
      "status": "completed",
      "created_at": "2022-02-12T16:26:04.680-06:00",
      "updated_at": "2022-02-12T16:26:08.071-06:00",
      "referer_url": "",
      "error": null,
      "media_asset_count": 1,
      "upload_media_assets": [
        {
          "id": 9370,
          "created_at": "2022-02-12T16:26:08.068-06:00",
          "updated_at": "2022-02-12T16:26:08.068-06:00",
          "upload_id": 4983629,
          "media_asset_id": 5206552,
          "status": "pending",
          "source_url": "https://i.pximg.net/img-original/img/2022/02/13/01/20/19/96198438_p0.jpg",
          "error": null,
          "page_url": "https://www.pixiv.net/artworks/96198438",
          "media_asset": {
            "id": 5206552,
            "created_at": "2022-02-12T16:26:07.980-06:00",
            "updated_at": "2022-02-12T16:26:08.061-06:00",
            "md5": "90a85a5fae5f0e86bdb2501229af05b7",
            "file_ext": "jpg",
            "file_size": 1055775,
            "image_width": 1052,
            "image_height": 1545,
            "duration": null,
            "status": "active"
          }
        }
      ]
    }

This is needed so you can check for upload errors in the API, since in a multi-file
upload, each asset can have a separate error message. This is a stopgap solution until
something like /uploads.json?include=upload_media_assets.media_asset works.

app/controllers/uploads_controller.rb

@@ -34,8 +34,8 @@ class UploadsController < ApplicationController
     case @mode
     when "table"
       @uploads = authorize Upload.visible(CurrentUser.user).paginated_search(params, count_pages: true)
-      @uploads = @uploads.includes(:uploader, media_assets: [:post]) if request.format.html?
-      respond_with(@uploads)
+      @uploads = @uploads.includes(:uploader, media_assets: :post, upload_media_assets: { media_asset: :post }) if request.format.html?
+      respond_with(@uploads, include: { upload_media_assets: { include: :media_asset }})
     when "gallery"
       @media_assets = authorize MediaAsset.active.visible(CurrentUser.user).includes(:post, uploads: [:uploader]).where(uploads: { uploader: CurrentUser.user }).paginated_search(params, count_pages: true).reorder("uploads.id DESC")
       respond_with(@media_assets)
@@ -57,7 +57,7 @@ class UploadsController < ApplicationController
       flash[:notice] = "Duplicate of post ##{@upload.media_assets.first.post.id}"
       redirect_to @upload.media_assets.first.post
     else
-      respond_with(@upload)
+      respond_with(@upload, include: { upload_media_assets: { include: :media_asset }})
     end
   end
 end