BUG: low variance arrays' kurtosis wrongfully set to zero

[dontgoto]

• [x] closes #57972 (Replace xxxx with the GitHub issue number)
• [x] Tests added and passed if fixing a bug or adding a new feature
• [ ] All code checks passed.
• [x] Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

This fixes an issue with low variance arrays' kurtosis. It was previously set to zero due to a cutoff that was chosen too conservatively.

[github-actions[bot]]

This pull request is stale because it has been open for thirty days with no activity. Please update and respond to this comment if you're still interested in working on this.

[mroeschke]

Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.