child pages do not appear in the Liferay 7.2 UI after upgrading

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.2.X, Master
• Fix Version/s: 7.2.10 DXP FP2, 7.2.10.1 DXP SP1, 7.2.1 CE GA2, 7.2.X, 7.3.10 DXP GA1, Master
• Component/s: DM > Upgrade
• Labels:
  • ee-bp
  • ee-ts
  • liferay-dxp-72-sp1
  • liferay-fixpack-dxp-2-7210
  • pt-upgrade-review
• Branch Version/s:
  7.2.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Sprint: 028 - Sandslash
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/75243

Description:
After upgrading from 7.0 to 7.2, child pages do not appear in the Liferay 7.2 UI.

Steps to Reproduce:
1. Startup Liferay 7.0 de-81
2. Create a few pages and create child pages for those pages. 
3. Upgrade using db_upgrade.sh and start server.

Expected Behavior:
The upgraded pages with child pages would show a dropdown arrow, as they do when created in 7.2.

Actual Behavior:
The upgraded pages do not have a dropdown to select the child pages.

Reproduced:
7.1.x: No 6f6a1236f8f1f22c218fbdfb27229b2424b4060e
Master: Yes 4f0ab9ebc11e36cb841edee620313996a7f27123