Assembler build error (navigation)

## Context

We had a failing assembler build even though all PRs that led to the failure state were green.

## Request

How can we minimize the chance of this happening again?

## Report

- Was trying to edit the cloud-enterprise TOC, and new entries were not being picked up ([error](https://github.com/elastic/docs-internal-workflows/actions/runs/18285271674/job/52058542324))
- An engineer discovered we had a duplicated TOC structure - one at the reference section level (one level above where I was editing), and one each for the cloud-enterprise and cloud-hosted reference content (where I was editing). He advised to include the child TOCs and remove the references to topics at the /reference level
- Locally previewed - rendered as expected
- Pushed change to GitHub - CI passed
- Checked preview in docs-v3-preview environment - rendered as expected
- Tech writer approved and I merged

Reported by @shainaraskas