Map Block Access resource into state when possible

[mitchnielsen]

Summary

As a follow-up to #204, we noted the following in internal/provider/resources/block_access.go:

NOTE: we are not currently mapping the response back into State,
as the Read payload is materially different from the Create/Update payloads.
This is something to be revisited in the future.

Acceptance criteria

• Map the response back into State whenever possible given potential changes to the Create/Update and Read payloads