Fixed compiler warnings.

Requests/DeleteTTSFilter.cs

@@ -14,13 +14,13 @@ namespace HermesSocketServer.Requests
             _logger = logger;
         }
 
-        public async Task<RequestResult> Grant(Channel channel, IDictionary<string, object> data)
+        public Task<RequestResult> Grant(Channel channel, IDictionary<string, object> data)
         {
             string filterId = data["id"].ToString()!;
             channel.Filters.Remove(filterId);
 
             _logger.Information($"Deleted a TTS filter by id [tts filter id: {filterId}]");
-            return RequestResult.Successful(null);
+            return Task.FromResult(RequestResult.Successful(null));
         }
     }
 }