Fix boxplot stats for all-masked input - #32515

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Marking as an autoclose candidate since the PR template was not filled out correctly and precommit hooks were not run. Please fill out the PR template as @lucaznch mentioned, disclose any use of AI, and address the precommit failures. Thank you!

The test failures are unrelated and should be fixed by #32516.

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Thanks for the feedback. I’ve completed the PR description template and added the AI disclosure. I also fixed the formatting issues and reran the relevant pre-commit hooks successfully. The focused tests pass locally: 13 passed.

Could the autoclose-candidate status be reviewed now?