[NUI] use proper constructor of ArgumentNullException (#1708)

use `ArgumentNullException(string paramName, string message);`
instead of `ArgumentNullException(string paramName);`.
`ArgumentNullException(string message);` doesn't exist.

Also, fixes CA2208

diff --git a/src/Tizen.NUI.Components/Controls/DropDown.cs b/src/Tizen.NUI.Components/Controls/DropDown.cs
index 6439225..399e15a 100755 (executable)
--- a/src/Tizen.NUI.Components/Controls/DropDown.cs
+++ b/src/Tizen.NUI.Components/Controls/DropDown.cs
@@ -849,11 +849,7 @@ namespace Tizen.NUI.Components
             [EditorBrowsable(EditorBrowsableState.Never)]
             public ViewHolder(View itemView)
             {
-                if (itemView == null)
-                {
-                    throw new ArgumentNullException("itemView may not be null");
-                }
-                this.ItemView = itemView;
+                ItemView = itemView ?? throw new ArgumentNullException(nameof(itemView), "itemView may not be null");
             }
 
             /// <summary>