Add missing kstats to dataset kstats

Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #16431
(cherry picked from commit 244ea5c4881f92a9d7c1fb341a49b127fda7539d)