Fixed Guid checks

Author: erwinvanhunen

src/Commands/Fields/AddField.cs

@@ -112,7 +112,7 @@ protected override void ExecuteCmdlet()
                         fieldCI.FieldOptions |= AddFieldOptions.AddToAllContentTypes;
                     }
 
-                    if (ClientSideComponentId != null)
+                    if (ClientSideComponentId != Guid.Empty)
                     {
                         fieldCI.ClientSideComponentId = ClientSideComponentId;
                     }
@@ -223,7 +223,7 @@ protected override void ExecuteCmdlet()
                     AddToDefaultView = AddToDefaultView
                 };
 
-                if (ClientSideComponentId != null)
+                if (ClientSideComponentId != Guid.Empty)
                 {
                     fieldCI.ClientSideComponentId = ClientSideComponentId;
                 }

src/Commands/Lists/GetListItem.cs

@@ -79,7 +79,7 @@ protected override void ExecuteCmdlet()
                 ClientContext.ExecuteQueryRetry();
                 WriteObject(listItem);
             }
-            else if (HasUniqueId())
+            else if (UniqueId != Guid.Empty)
             {
                 CamlQuery query = new CamlQuery();
                 var viewFieldsStringBuilder = new StringBuilder();
@@ -180,11 +180,6 @@ private bool HasId()
             return Id != -1;
         }
 
-        private bool HasUniqueId()
-        {
-            return UniqueId != null && UniqueId != Guid.Empty;
-        }
-
         private bool HasCamlQuery()
         {
             return Query != null;