Describe the bug
If a field inside a collapsed object fires a validation error, the entry will not be saved. This is the correct behavior, but the problem is, that there is no indication of where the error occurs.

To Reproduce
Steps to reproduce the behavior. For example:

1. Create an object field and add collapsed: true
2. Add a required sub-field
3. Leave the sub-field empty and try to save the entry.
4. See a general error notification at the top and observe that there is no notification on the collapsed object

Expected behavior
If a field is collapsed and it includes objects with validation errors, it should also be treated as a field with an error. It should get a red border and an explanation text in red color.

Screenshots
Collapsed - there is no indication that a required filed is empty in services object

Uncollapsed

Applicable Versions:

• Netlify CMS version: 2.10.147
• Git provider: GitHub
• OS: MacOS 11.4 (20F71)
• Browser version: Brave 1.26

CMS configuration
Example configuration for a collapsed object with a required string field. This happens on any global configuration I believe.

{name: services, widget: object, collapsed: true, summary: fields: [
  {name: title, widget: string}
]}