Fix tutorial download state not matching correctly when already available locally

Closes https://github.com/ppy/osu/issues/18468.

This doesn't stop the tutorial from downloading a second time, but at
least displays the correct status afterwards. Avoiding the download is a
bit more involved and requires a change to the flow. Probably not worth
it just yet.

To test, recommend switching to production environment, as dev server
doesn't have correct metadata for tutorial resulting in weirdness.

osu.Game/Beatmaps/Drawables/BundledBeatmapDownloader.cs

@@ -85,6 +85,8 @@ namespace osu.Game.Beatmaps.Drawables
                 downloadTrackers.Add(beatmapDownloadTracker);
                 AddInternal(beatmapDownloadTracker);
 
+                // Note that this is downloading the beatmaps even if they are already downloaded.
+                // We could rely more on `BeatmapDownloadTracker`'s exposed state to avoid this.
                 beatmapDownloader.Download(beatmapSet);
             }
         }