ID passed to SchemaLoader::loadObjectSchema() should take precedence over $id in schema data

[bradjones1]

Sometimes schema files have more specific $ids than their well-known/canonical URLs. E.g.,

https://jsonapi.org/schema vs. https://jsonapi.org/schemas/spec/v1.0/draft

I may be using a local file with that more specific/versioned $id, but other schemas will reference the canonical version. If I choose to explicitly set the ID in ::loadObjectSchema(), we should use that. Except, it's overridden at

json-schema/src/Parsers/SchemaParser.php

Lines 346 to 349 in c48df6d

	if (property_exists($schema, '$id')) {
	$existent = true;
	$id = Uri::parse($schema->{'$id'}, true);
	}