fix: classify Plex music releases correctly (#6977)

* fix: classify Plex music releases correctly

* test(plex): cover music release classification

apps/docs/docs/integrations/plex/index.mdx

@@ -19,6 +19,8 @@ import { mediaReleasesWidget } from "@site/docs/widgets/media-releases";
 
 <IntegrationCapabilites items={[{ widget: mediaServerWidget }, { widget: mediaReleasesWidget }]} />
 
+The Media releases widget classifies Plex albums, artists, and tracks as Music.
+
 ### Adding the integration
 
 <AddingIntegration />