ContainSubtree does not have an overload taking an options builder

The override with the config callback is defined for BeEquivalentTo:

```
public AndConstraint<JTokenAssertions> BeEquivalentTo(JToken expected,
            Func<IJsonAssertionOptions<object>, IJsonAssertionOptions<object>> config,
            string because = "",
            params object[] becauseArgs)
```

but not for ContainSubtree