`dismiss_notification` reports failure on successful 204 response

[C-Ross]

When using the dismiss_notification tool to mark notifications as done, the operation succeeds (HTTP 204 No Content) but the tool reports it as a failure:

failed to mark notification as done: unexpected status 204:

HTTP 204 is the expected success response for this endpoint per the GitHub API documentation.

Expected behavior: The tool should return success when receiving a 204 response.

Actual behavior: The tool returns an error message indicating failure despite the operation completing successfully.

[SamMorrowDrums]

Thanks this is a really helpful report.