Assign Assert results to discard in unit test

Updated assertions in Test_RelayCommandAttribute_WithPartialCommandMethodDefinitions to assign results to the discard variable, improving code clarity and suppressing possible warnings about unused return values.

Author: Sergio0694

tests/CommunityToolkit.Mvvm.UnitTests/Test_RelayCommandAttribute.cs

@@ -665,10 +665,10 @@ public void Test_RelayCommandAttribute_WithPartialCommandMethodDefinitions()
     {
         ModelWithPartialCommandMethods model = new();
 
-        Assert.IsInstanceOfType<RelayCommand>(model.FooCommand);
-        Assert.IsInstanceOfType<RelayCommand<string>>(model.BarCommand);
-        Assert.IsInstanceOfType<RelayCommand>(model.BazCommand);
-        Assert.IsInstanceOfType<AsyncRelayCommand>(model.FooBarCommand);
+        _ = Assert.IsInstanceOfType<RelayCommand>(model.FooCommand);
+        _ = Assert.IsInstanceOfType<RelayCommand<string>>(model.BarCommand);
+        _ = Assert.IsInstanceOfType<RelayCommand>(model.BazCommand);
+        _ = Assert.IsInstanceOfType<AsyncRelayCommand>(model.FooBarCommand);
 
         FieldInfo bazField = typeof(ModelWithPartialCommandMethods).GetField("bazCommand", BindingFlags.Instance | BindingFlags.NonPublic)!;