Hidden subfield is not selectable

[sebdeleze]

Describe the issue
Following this structure:

"publication": {
    "title": "Publication",
    "type": "object",
    "additionalProperties": false,
    "properties": {
        "startDate": {
            "title": "Start date",
            "type": "string",
            "minLength": 1,
            "form": {
                "hide": true
            }
        },
        "statement": {
            "title": "Statement",
            "type": "string",
            "minLength": 1
        }
    }
}

The startDate field is not displayed by default in the editor, but could be selectable in the dropdown after the parent's label. The dropdown appears well, but contains nothing.

To Reproduce
Steps to reproduce the behavior:

1. Go to document's editor in SONAR https://sonardev.test.rero.ch/manage/records/documents/new.
2. Choose Book chapter for document type.
3. Go to Contained in (host document) section.
4. Click the dropdown after Publication.
5. The dropdown is empty.

Expected behavior
The dropdown must contain the choice for adding field Start date.

Screenshots

[sebdeleze]

Dublicates of #327.