Remove breaking change to IPresence interface with a note for 2.1

src/Discord.Net.Core/Entities/Users/IPresence.cs

@@ -18,6 +18,7 @@ namespace Discord
         /// <summary>
         ///     Gets the set of clients where this user is currently active.
         /// </summary>
-        IImmutableSet<ClientType> ActiveClients { get; }
+        // TODO: Un-comment ActiveClients definition in IPresence for 2.1.x breaking update
+        // IImmutableSet<ClientType> ActiveClients { get; }
     }
 }