[BUG] allOf generates false import with typescript-angular format

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

False import. When using allOf with 2 objects of different type.

openapi-generator version

6.4.0

OpenAPI declaration file content or url

{
  "openapi": "3.0.0",
  "info": {
    "title": "allOf bug example",
    "version": "1"
  },
  "paths": {
    "/foo": {
      "get": {
        "tags": [
          "entry"
        ],
        "responses": {
          "200": {
            "description": "200 Response"
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "ConvertableFileSchema": {
        "type": "object",
        "properties": {
          "inputFormat": {
            "allOf": [
              {
                "$ref": "#/components/schemas/InputFormatEnum"
              },
              {
                "type": "object"
              }
            ]
          }
        }
      },
      "InputFormatEnum": {
        "type": "string"
      }
    }
  }
}

Steps to reproduce

Run openapi-generator-cli generate -i [PATH_TO_JSON] -g typescript-angular -o [OUTPUT_PATH]

Run the provided OpenAPI declaration through openapi-generator-cli with the typescript-angular generator and inspect the generated imports. Compare the output with the expected imports for the allOf property, then add coverage for the example so the generated client no longer contains the false import.