Overriding the `AccessEntry#_properties` with a deep copy of the API resource overwrites the `role` property set in `AccessEntry.__init__` which isn't present in the resource if the `role` is set to `None`. This causes `AccessEntry`s generated from API representations to no longer evaluate to equal with equivalent `AccessEntry` resources instantiated through `AccessEntry.__init__`. The added unit test fails without the change and passes with the change.