server: don't dispose of cache thanks

UwuRadio.Server/Services/DownloadService.cs

@@ -10,7 +10,7 @@ public record SongFileInfo(FileInfo File, string Md5, Duration Length);
 /// <summary>
 ///     This service downloads songs when required and keeps track of them on disk
 /// </summary>
-public class DownloadService : IDisposable
+public class DownloadService
 {
 	private readonly Queue<Song>                      _downloadQueue     = new();
 	private readonly Dictionary<string, SongFileInfo> _fileInfos         = new();
@@ -20,8 +20,6 @@ public class DownloadService : IDisposable
 
 	public DownloadService() { Directory.CreateDirectory(Constants.C.CacheFolder); }
 
-	public void Dispose() => Directory.Delete(Constants.C.CacheFolder, true);
-
 	public bool IsBlacklisted(Song song) => _downloadBlacklist.Contains(song.Id);
 
 	public void EnsureDownloaded(Song song)