Safe navigator for nil responses

Hello,

Seems hardly worth submitting a PR for this one.  I've come across instances of a nil response, so would recommend adding a safe navigator to this call, ie:

`      initialize_from(response&.with_indifferent_access)`

https://github.com/HubspotCommunity/hubspot-ruby/blob/8eb0a64dd0c14c79e631e81bfdc169583e775a46/lib/hubspot/resource.rb#L137

Thanks.