Update src/libraries/System.ComponentModel.TypeConverter/tests/TypeDescriptorTests.cs

Co-authored-by: Copilot <[email protected]>

Author: alexey-zakharov

src/libraries/System.ComponentModel.TypeConverter/tests/TypeDescriptorTests.cs

@@ -1588,8 +1588,7 @@ public static void TypeDescriptor_DoesNotKeepUnloadableTypes()
                     Type? collectibleType = assembly.GetType("UnloadableTestTypes.SimpleType");
                     Assert.NotNull(collectibleType);
                     Type? collectibleAttributeType = assembly.GetType("UnloadableTestTypes.SimpleTypeAttribute");
-                    Assert.NotNull(collectibleType);
-                    Attribute? collectibleAttribute = collectibleType.GetCustomAttribute(collectibleAttributeType);
+                    Assert.NotNull(collectibleAttributeType);
                     Assert.NotNull(collectibleAttribute);
 
                     // Cache the type's cachable entities