Add name validation for PropertyOverride and FieldOverride

### Description

The current implementation allows creation of overrides without specifying a field or property name.
```C#
var field = new FieldOverride(null, null);
var property = new PropertyOverride(null, null);
```

This is an error, and such overrides cause exceptions later on in the resolution. This condition must be handled in the constructor and throw `ArgumentNullException`.
