[CLN] Make delete return None

[itaismith]

Description of changes

The Collection.delete API seemingly returns None, but our internal implementation returns a list of the IDs that were deleted. This PR makes all delete implementations return None for consistency.

Test plan

How are these changes tested?

• [x] Tests pass locally with pytest for python, yarn test for js, cargo test for rust

Documentation Changes

The documentation does not mention the API returning a list of deleted IDs, so it is consistent with the expected behavior.

[github-actions[bot]]

Reviewer Checklist

Please leverage this checklist to ensure your code review is thorough before approving

Testing, Bugs, Errors, Logs, Documentation

• [ ] Can you think of any use case in which the code does not behave as intended? Have they been tested?
• [ ] Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• [ ] If appropriate, are there adequate property based tests?
• [ ] If appropriate, are there adequate unit tests?
• [ ] Should any logging, debugging, tracing information be added or removed?
• [ ] Are error messages user-friendly?
• [ ] Have all documentation changes needed been made?
• [ ] Have all non-obvious changes been commented?

System Compatibility

• [ ] Are there any potential impacts on other parts of the system or backward compatibility?
• [ ] Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• [ ] Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[HammadB]

Can we add a simple unit test