Remove unused usings in CaseFilter

CoviDok/Api/Request/CaseFilter.cs

@@ -1,10 +1,4 @@
-using CoviDok.Data;
+namespace CoviDok.Api.Request
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
-
-namespace CoviDok.Api.Request
 {
     public class CaseFilter
     {