refactor: subscribe to onChange instead of waiting for the event to be received from the manager

Endpoint/Common/Services/ScheduleSyncManager.cs

@@ -4,12 +4,7 @@ namespace Mirea.Api.Endpoint.Common.Services;
 
 public static class ScheduleSyncManager
 {
-    public static event Action? OnUpdateIntervalRequested;
     public static event Action? OnForceSyncRequested;
-
-    public static void RequestIntervalUpdate() =>
-        OnUpdateIntervalRequested?.Invoke();
-
     public static void RequestForceSync() =>
         OnForceSyncRequested?.Invoke();
 }