Configuration of IJsonAssertionOptions slows down comparison a log

To check doubles using precision when comparing JSON's, I am using the following options callback in `BeEquivalentTo`:

```cs
options => options.Using(d => d.Subject.Should().BeApproximately(d.Expectation, 0.001))
.WhenTypeIs()
```

But it seems that this builder callback is being called for every value comparison.
JTokenDifferentiator.CompareValues contains:

```cs
using (var scope = new AssertionScope())
{
actual.Value.Should().BeEquivalentTo(expected.Value, options =>
(JsonAssertionOptions)config.Invoke(new JsonAssertionOptions(options)));

hasMismatches = scope.Discard().Length > 0;
}
```

With the addition of the Using, a bigger json (MB's) goes from 200ms to +10s on my PC.

As a workaround, I replicated the behavior of the builder by accessing the `userEquivalencySteps` field on `SelfReferenceEquivalencyAssertionOptions` using reflection and inserting a custom `IEquivalencyStep`, instead of using the fluent API.
This brings it to 1s, which is acceptable for my use case.

Would it make sense to not call this options callback for every JSON value and build it once?
Or would adding API to add a custom `IEquivalencyStep` instead of the builder make sense?

Inizia da JTokenDifferentiator.CompareValues e segui il modo in cui config.Invoke crea JsonAssertionOptions per ogni confronto di valori. Riproduci il rallentamento segnalato con un documento JSON di grandi dimensioni e il callback Using, quindi confronta il comportamento dopo aver modificato il flusso delle options. Il lavoro è completato quando viene preservato il confronto di precisione, si evita il lavoro ripetuto del builder e si dimostrano prestazioni accettabili.

Scritto dal modello di indicizzazione a partire dal testo della issue.