feat(MessageEmbed): change toJSON method to return an api-compatible object (#3813)

src/structures/APIMessage.js

@@ -152,7 +152,7 @@ class APIMessage {
     } else if (this.options.embed) {
       embedLikes.push(this.options.embed);
     }
-    const embeds = embedLikes.map(e => new MessageEmbed(e)._apiTransform());
+    const embeds = embedLikes.map(e => new MessageEmbed(e).toJSON());
 
     let username;
     let avatarURL;

src/structures/MessageEmbed.js

@@ -317,16 +317,11 @@ class MessageEmbed {
     return this;
   }
 
-  toJSON() {
-    return Util.flatten(this, { hexColor: true });
-  }
-
   /**
-   * Transforms the embed object to be processed.
+   * Transforms the embed to a plain object.
    * @returns {Object} The raw data of this embed
-   * @private
    */
-  _apiTransform() {
+  toJSON() {
     return {
       title: this.title,
       type: 'rich',