Fix Transcode Cleanup Schedule

Sets the default time to midnight, and confirms to the same task
scheduling commands that other tasks use.

Emby.Server.Implementations/ScheduledTasks/Tasks/DeleteTranscodeFileTask.cs

@@ -41,7 +41,13 @@ namespace Emby.Server.Implementations.ScheduledTasks.Tasks
         /// Creates the triggers that define when the task will run.
         /// </summary>
         /// <returns>IEnumerable{BaseTaskTrigger}.</returns>
-        public IEnumerable<TaskTriggerInfo> GetDefaultTriggers() => new List<TaskTriggerInfo>();
+        public IEnumerable<TaskTriggerInfo> GetDefaultTriggers()
+        {
+            return new[]
+            {
+                new TaskTriggerInfo { Type = TaskTriggerInfo.TriggerDaily, TimeOfDayTicks = TimeSpan.FromHours(0).Ticks}
+            };
+        }
 
         /// <summary>
         /// Returns the task to be executed.