MockSchemaRegistryClient only supports Avro schema provider by default

[mcpheesvoz]

MockSchemaRegistryClient should by default support the three main schema types, instead of only Avro:

    this.providers = providers != null && !providers.isEmpty()
                     ? providers.stream().collect(Collectors.toMap(p -> p.schemaType(), p -> p))
                     : Collections.singletonMap(AvroSchema.TYPE, new AvroSchemaProvider());

When your schema is configured with properties / or spring application.yml it's impossible to override this current;y