Schema incorrect for config entity "fields" that are Maps and Sequences

Problem/Motivation

Discovered while working on https://www.drupal.org/project/field_ui_modern.

For example:

{
  "$schema": "https://json-schema.org/draft/2019-09/hyper-schema",
  "$id": "http://core.test/jsonapi/field_storage_config/field_storage_config/resource/schema",
  "title": "Field storage",
  "allOf": [
    {
      "type": "object",
      "properties": {
        "type": {
          "$ref": "#/definitions/type"
        },
        "attributes": {
          "$ref": "#/definitions/attributes"
        }
      }
    },
    {
      "$ref": "https://jsonapi.org/schema#/definitions/resource"
    }
  ],
  "definitions": {
    "type": {
      "const": "field_storage_config--field_storage_config"
    },
    "attributes": {
      "properties": {
        "drupal_internal__id": {
          "type": "string",
          "title": "drupal_internal__id"
        },
        "langcode": {
          "type": "string",
          "title": "langcode"
        },
        "status": {
          "type": "boolean",
          "title": "status"
        },
        "dependencies": {
          "title": "dependencies"
        },
        "third_party_settings": {
          "type": "array",
          "items": {
            "properties": {
              "third_party_settings": {
                "title": "third_party_settings"
              }
            }
          }
        },
        "field_name": {
          "type": "string",
          "title": "field_name"
        },
        "entity_type": {
          "type": "string",
          "title": "entity_type"
        },
        "field_storage_config_type": {
          "type": "string",
          "title": "field_storage_config_type"
        },
        "settings": {
          "title": "settings"
        },
        "module": {
          "type": "string",
          "title": "module"
        },
        "locked": {
          "type": "boolean",
          "title": "locked"
        },
        "cardinality": {
          "type": "integer",
          "title": "cardinality"
        },
        "translatable": {
          "type": "boolean",
          "title": "translatable"
        },
        "indexes": {
          "type": "array",
          "items": {
            "properties": {
              "indexes": {
                "title": "indexes"
              }
            }
          }
        },
        "persist_with_no_fields": {
          "type": "boolean",
          "title": "persist_with_no_fields"
        },
        "custom_storage": {
          "type": "boolean",
          "title": "custom_storage"
        }
      },
      "description": "Entity attributes",
      "type": "object",
      "additionalProperties": false
    }
  }
}

→ note how

        "dependencies": {
          "title": "dependencies"
        },

does not specify any type — it should be a type: object, with the potential keys being module, theme, config and content.

Same for other "fields" (top-level properties) like settings — although that one is field-type-specific, which I'm not sure how we can express in JSON Schema.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes