fix compiler warnings

Author: sjefvanleeuwen

src/Blazor.AdminLte/SideBar/SideBarMenuItem.razor

@@ -12,8 +12,6 @@
 </li>
 @code {
 
-    private string Id = Guid.NewGuid().ToString();
-
     [Parameter]
     public string Icon { get; set; }
     [Parameter]
@@ -23,8 +21,6 @@
 
     private SideBarState State => GetState<SideBarState>();
 
-    private SideBarState.SelectMenuItemAction action;
-
     private void Click()
     {
         nav.NavigateTo(Link);