[BUG] Generator changes nested type to object when used in referenced file

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When a schema references another schema as its property the property type is only correct in the generated code if the reference is defined in the base file

openapi-generator version

5.1.1

OpenAPI declaration file content or url

example is derived from https://swagger.io/docs/specification/data-models/data-types/ the Nested Objects section
i'm using the aspnetcore generator in the example but the behavior is them same using typescript-angular

Example 1:

index.yml

components:
  schemas:
    User:
        type: object
        properties:
          id:
            type: integer
          name:
            type: string
          contact_info:
            $ref: '#/components/schemas/ContactInfo'
    
    ContactInfo:
        type: object
        properties:
          email:
            type: string
            format: email
          phone:
            type: string

this produces the expected output

public class User : IEquatable<User>
{
   ...

    /// <summary>
    /// Gets or Sets ContactInfo
    /// </summary>
    [DataMember(Name="contact_info", EmitDefaultValue=false)]
    public ContactInfo ContactInfo { get; set; }
}

example 2:

index.yml

components:
  schemas:
    User:
        type: object
        properties:
          id:
            type: integer
          name:
            type: string
          contact_info:
            $ref: '#/components/schemas/ContactInfo'
    
    ContactInfo:
        $ref: './models/otherfile.yml#/components/schemas/ContactInfo

./models/otherfile.yml

components:
  schemas:
    ContactInfo:
      type: object
      properties:
        email:
          type: string
          format: email
        phone:
          type: string

this also produces the expected output

public class User : IEquatable<User>
{
   ...

    /// <summary>
    /// Gets or Sets ContactInfo
    /// </summary>
    [DataMember(Name="contact_info", EmitDefaultValue=false)]
    public ContactInfo ContactInfo { get; set; }
}

Example 3:

index.yml

components:
  schemas:
    User:
      $ref: './models/otherfile.yml#/components/schemas/User'
    ContactInfo:
      $ref: './models/otherfile.yml#/components/schemas/ContactInfo'

./models/otherfile.yml

components:
  schemas:
    User:
        type: object
        properties:
          id:
            type: integer
          name:
            type: string
          contact_info:
            $ref: '#/components/schemas/ContactInfo'
    
    ContactInfo:
        type: object
        properties:
          email:
            type: string
            format: email
          phone:
            type: string

public class User : IEquatable<User>
{
   ...

    /// <summary>
    /// Gets or Sets ContactInfo
    /// </summary>
    [DataMember(Name="contact_info", EmitDefaultValue=false)]
    public Object ContactInfo { get; set; }
}

In this case the ContactInfo property is typed as Object rather than 'ContactInfo'

Generation Details

{
  "$schema": "../../node_modules/@openapitools/openapi-generator-cli/config.schema.json",
  "spaces": 2,
  "generator-cli": {
    "version": "5.1.1",
    "generators": {
      "server": {
        "generatorName": "aspnetcore",
        "output": "#{cwd}/../.generated",
        "glob": "src/*.{json,yaml,yml}",
        "modelNameSuffix": "",
        "modelPackage": "MyComp.CommonData.Data",
        "apiNameSuffix": "Base",
        "apiPackage": "MyComp.CommonData",
        "additionalProperties": {
          "aspnetCoreVersion": "5.0",
          "packageName": "OpenApi.Generated",
          "classModifier": "abstract",
          "buildTarget": "library",
          "isLibrary": true,
          "operationIsAsync": true,
          "operationResultTask": true,
          "operationModifier": "abstract",
          "swashbuckleVersion": "5.0.0"
        }
      },
      "ng-client": {
        "generatorName": "typescript-angular",
        "glob": "src/*.{json,yaml,yml}",
        "output": "#{cwd}/../../.clients/ng",
        "additionalProperties": {
          "npmName": "@mycomp/ngclient-webservice-common-data",
          "npmVersion": "0.0.0",
          "npmRepository": "https://npm.pkg.github.com",
          "providedIn": "root",
          "serviceFileSuffix": ".api",
          "serviceSuffix": "Api"
        }
      }
    }
  }
}

Steps to reproduce

see examples

Related issues/PRs

Suggest a fix

Start with the index.yml and ./models/otherfile.yml examples, especially example 3, and reproduce the issue with the aspnetcore or typescript-angular generator using version 5.1.1. Compare the generated User.ContactInfo type with the expected ContactInfo type. Done means referenced nested schemas retain their named type when the schema is defined in another file.