WIP - RUBY-3671 - Hash should honor BSON::Registry

[johnnyshields]

Fixes RUBY-3671

There is a BSON::Registry which determines how BSON is deserialized. For example, Mongoid has this code:

ifallow_decimal128BSON::Registry.register(BSON::Decimal128::BSON_TYPE,BSON::Decimal128)elseBSON::Registry.register(BSON::Decimal128::BSON_TYPE,BigDecimal)end

However, BSON gem does not honor this registry for Hash, it always deserializes as BSON::Document, even when the registry is set to Hash.

[codeowners-service-app]

Assigned alexbevi for team dbx-ruby because comandeo-mongo is out of office.