fix(multitenancy): remove unnecessary using blocks

aspnet-core/modules/tenants/LINGYUN.Abp.MultiTenancy.RemoteService/LINGYUN/Abp/MultiTenancy/RemoteService/EventBus/Distributed/TenantSynchronizer.cs

@@ -82,8 +82,6 @@ public class TenantSynchronizer :
     }
 
     protected virtual async Task RemoveCacheItemAsync(Guid tenantId, string tenantName = null)
-    {
-        using (_currentTenant.Change(null))
     {
         using (_currentTenant.Change(null))
         {
@@ -94,5 +92,4 @@ public class TenantSynchronizer :
             }
         }
     }
-    }
 }