Regression bug on circular object references

[detomarco]

Describe the bug

• A clear and concise description of what the bug is: the title of an issue is not enough

Starting from 2.8.7 we noticed a regression bug related to circular object references.

Given these kotlin classes

data class Account(
    val id: String,
    val subs: List<Subscriptions>
)

data class Subscriptiong(
   val id: String.
) {

    var account: Account
}

To Reproduce
Steps to reproduce the behavior:

• What version of spring-boot you are using?
  3.4.5
• What modules and versions of springdoc-openapi are you using?
  springdoc-openapi-starter-webmvc-ui
• What is the actual and the expected result using OpenAPI Description (yml or json)?

## ACTUAL
{
      "Account": {
        "type": "object",
        "properties": {
          "id": {
            "type": "integer",
            "format": "int64"
          },
          "subscriptions": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/Subscription"
            }
          }
        }
      },
      "Subscription": {
        "type": "object",
        "properties": {
          "id": {
            "type": "integer",
            "format": "int64"
          },
          "account": {
            "required": [ ## there should be a reference to Account here
              "id"
            ]
          }
        }
      }

• Provide with a sample code (HelloController) or Test that reproduces the problem

Expected behavior

## EXPECTED (as in v2.8.6)

{

      "Account": {
        "type": "object",
        "properties": {
          "id": {
            "type": "integer",
            "format": "int64"
          },
          "subscriptions": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/Subscription"
            }
          }
        },
      },
      "Subscription": {
        "type": "object",
        "properties": {
          "id": {
            "type": "integer",
            "format": "int64"
          },
          "account": {
            "$ref": "#/components/schemas/Account"
          }
        },
      },

}
}

• A clear and concise description of what you expected to happen.
• What is the expected result using OpenAPI Description (yml or json)?

Screenshots
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Additional context
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