Show item that's missing in exception when rendering a page

• Type: Task
• Status: Closed
• Priority: Minor
• Resolution: Completed
• Affects Version/s: None
• Fix Version/s: 7.4.1 CE GA2, 7.4.13 DXP GA1, Master
• Component/s: Pages > Content Pages
• Labels:
  • fc_21_05
• Epic/Theme:
  • Technical_Debt
• Git Pull Request: https://github.com/liferay-echo/liferay-portal/pull/4603

There are cases were there's a NPE when retrieving the items for a fragment based page, and we don't give enough information to the user. This task is to give more information to the user as to which item has failed to be retrieved