fix(PartialGroupDMChannel): Prevent undefined values (#10889)

fix(PartialGroupDMChannel): prevent `undefined` values

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: Jiralite

packages/discord.js/src/structures/PartialGroupDMChannel.js

@@ -27,7 +27,7 @@ class PartialGroupDMChannel extends BaseChannel {
      * The hash of the channel icon
      * @type {?string}
      */
-    this.icon = data.icon;
+    this.icon = data.icon ?? null;
 
     /**
      * Recipient data received in a {@link PartialGroupDMChannel}.
@@ -39,7 +39,7 @@ class PartialGroupDMChannel extends BaseChannel {
      * The recipients of this Group DM Channel.
      * @type {PartialRecipient[]}
      */
-    this.recipients = data.recipients;
+    this.recipients = data.recipients ?? [];
 
     /**
      * A manager of the messages belonging to this channel