docs(samples): deprecate client.dataset method

[steffnay]

• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

🦕🐢

[shollyman]

The changes to the snippets look great.

There's one thing here of concern, and that's the project field of the client. It's not currently a property, should it be? I believe in some cases the project is derived indirectly (e.g. from credentials), and we should either try to resolve this, or throw an error that the project isn't set explicitly.