[BUG] [typescript-axios] Upload file with multipart misses to add boundary with node

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 using typescript-axios in a node environment, it's not able to upload a image because axios does not automatically add the boundary to the header, ref see here.

openapi-generator version

2.1.6

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: Bug API
  version: 1.0.0
tags:
  - name: image
    description: Upload a image
paths:
  /image:
    put:
      tags:
        - image
      summary: Update current map image
      operationId: setImage
      requestBody:
        content:
          multipart/form-data:
            schema:
              properties:
                file:
                  type: string
                  format: binary
                  description: The file to upload
      responses:
        200:
          description: Image successful uploaded

Generation Details

npx @openapitools/openapi-generator-cli generate -i bug-spec.yaml -g typescript-axios --additional-properties supportsES6=true -o generated

Steps to reproduce

Execute the command above and take a look at ImageApiAxiosParamCreator:54.

localVarHeaderParameter['Content-Type'] = 'multipart/form-data';

Related issues/PRs

Suggest a fix

I already have an idea how it could be fixed, but I have to say that I only have beginner experience, so please check if it makes sense.

if (typeof((localVarFormParams as any).getHeaders) === 'function') {
  const headers = (localVarFormParams as any).getHeaders();
  for (const [key, value] of Object.entries(headers)) {
    localVarHeaderParameter[key] = value;
  }
} else {
  localVarHeaderParameter['Content-Type'] = 'multipart/form-data';
}

Reproduce the issue with the provided OpenAPI declaration and typescript-axios generation command, then inspect ImageApiAxiosParamCreator:54 in the generated output. Verify the Node multipart upload sends the boundary in its Content-Type header; the issue is done when the generated client uploads the image successfully.