[BUG] [Rust Server] Not support free-form object code generated issue.

Created by: paladinzh

Bug Report Checklist

Have you provided a full/minimal spec to reproduce the issue?
Have you validated the input using an OpenAPI validator (example)?
What's the version of OpenAPI Generator used?
Have you search for related issues/PRs?
What's the actual output vs expected output?
[Optional] Bounty to sponsor the fix (example)

Description

Not support free-form object code generated

openapi-generator version

OpenAPI declaration file content or url

modules/openapi-generator/src/test/resources/3_0/rust-server/openapi-v3.yaml get: tags: [Repo, Info] operationId: Get Repo\Info responses: "200": description: OK content: application/json: schema: $ref: "#/components/schemas/RepoObject"

RepoObject: type: object

Command line used for generation

bin/rust-server-petstore.sh

Steps to reproduce

Run the generated code openapi-v3/

Related issues/PRs

Suggest a fix

Allow generate free-form object.