Required fields aren't being validated

Ref #129499 Required properties behave strangely with object settings in the settings editor. Let's say A is required and B isn't. Then consider the following setting value: ```json "settingName": { "B": "v2" } ``` and assume A has a default value of v1. The JSON editor displays a warning saying A is missing. However, the GUI editor displays A with the value v1, still, with no warning. However, if A isn't given a default value, but is still required, the GUI editor doesn't display A, but there's still no warning on the GUI editor side.