feat(ytmusic): implement music#Library (#136)

* feat: add ItemSectionTab and related parsers

* feat: add `continuation` to `Grid`parser class

* feat (ytmusic): implement music#getLibrary()

* Improve album fetch in `MusicResponsiveListItem`

* music#Library: return [] for empty results

* feat: add `Dropdown` & `DropdownItem` parsers

* feat: add `CreatePlaylistDialog` parser

* feat: add `create_playlist` to NavigationEndpoint

* feat: add `AutomixPreviewVideo` parser

* feat: improve parsing of items

* fix: `PlaylistPanel` continuation

* feat: more args in `Actions#next`

* feat: add `PlaylistPanelContinuation` to `Parser`

* chore: update parser-map

* music#Library: refactor + add shuffle songs opt

* feat: add `endpoint` to `DropdownItem`

* feat: add `end_items` to `ItemSectionTabbedHeader`

* feat(ytmusic): add `sort_by` to `music#Library`

src/parser/classes/DropdownItem.ts

@@ -0,0 +1,34 @@
+import { YTNode } from '../helpers';
+import Text from './misc/Text';
+import NavigationEndpoint from './NavigationEndpoint';
+
+class DropdownItem extends YTNode {
+  static type = 'DropdownItem';
+
+  label: string;
+  selected: boolean;
+  value?: number;
+  iconType?: string;
+  endpoint?: NavigationEndpoint;
+
+  constructor(data: any) {
+    super();
+
+    this.label = new Text(data.label).toString();
+    this.selected = !!data.isSelected;
+
+    if (data.int32Value) {
+      this.value = data.int32Value;
+    }
+
+    if (data.onSelectCommand?.browseEndpoint) {
+      this.endpoint = new NavigationEndpoint(data.onSelectCommand);
+    }
+
+    if (data.icon?.iconType) {
+      this.iconType = data.icon?.iconType;
+    }
+  }
+}
+
+export default DropdownItem;