fix(Channel): type mismatch in subscribe_button prop

The `subscribe_button` property can also be of type `Button`.

src/parser/classes/Channel.ts

@@ -5,6 +5,7 @@ import Author from './misc/Author.js';
 import NavigationEndpoint from './NavigationEndpoint.js';
 
 import SubscribeButton from './SubscribeButton.js';
+import Button from './Button.js';
 
 import { YTNode } from '../helpers.js';
 
@@ -36,9 +37,9 @@ class Channel extends YTNode {
     this.long_byline = new Text(data.longBylineText);
     this.short_byline = new Text(data.shortBylineText);
     this.endpoint = new NavigationEndpoint(data.navigationEndpoint);
-    this.subscribe_button = Parser.parseItem(data.subscribeButton, SubscribeButton);
+    this.subscribe_button = Parser.parseItem(data.subscribeButton, [SubscribeButton, Button]);
     this.description_snippet = new Text(data.descriptionSnippet);
   }
 }
 
-export default Channel;
+export default Channel;