fix(lidarr): Change monitor to Existing to properly add artist #3597

Discussed and tested manually in https://github.com/Lidarr/Lidarr/issues/3597#issuecomment-1530804055

src/Ombi.Core/Senders/MusicSender.cs

@@ -100,7 +100,7 @@ namespace Ombi.Core.Senders
                     addOptions = new Addoptions
                     {
                         monitored = true,
-                        monitor = MonitorTypes.None,
+                        monitor = MonitorTypes.Existing,
                         searchForMissingAlbums = false,
                         AlbumsToMonitor = new[] {model.ForeignAlbumId}
                     },
@@ -199,4 +199,4 @@ namespace Ombi.Core.Senders
             return new SenderResult { Message = "Could not set album to monitored", Sent = false, Success = false };
         }
     }
-}
+}