[BUG][Python][Client] Incorrect import path if packageName is nested

Created by: chebykinn

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 I generate a client with --package-name some.nested.path the dots will be replaced with slashes in a generated endpoint file. So expected generated import line is:

from pysvc1.generated.openapi.clients.service1.models.resp import Resp

Actual:

from pysvc1/generated/openapi/clients/service1.models.resp import Resp

I've narrowed it down to this method: https://github.com/OpenAPITools/openapi-generator/blob/02916822f73be0939caf7a360ead5342e1b07b75/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java#L890-L893 Here it uses packagePath which explicitly replaces dots with slashes: https://github.com/OpenAPITools/openapi-generator/blob/02916822f73be0939caf7a360ead5342e1b07b75/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java#L2620-L2622

openapi-generator version

6.2.0

OpenAPI declaration file content or url

openapi: "3.0.0"
info:
  version: 1.0.0
  title: service1
  description: Service description
  contact:
    name: Maintainer name
    email: Maintainer email
servers:
  - url: service1.company.com
paths:
  /path/to/api:
    get:
      summary: sample handler
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Resp'
components:
  schemas:
    Resp:
      type: object
      properties:
        prop1:
          type: string
        prop2:
          type: string
      required:
        - prop2

Generation Details

openapi-generator generate -g python  -i ./api.yaml -o ./out --package-name pysvc1.generated.openapi.clients.service1

Steps to reproduce

Run client generation with a nested package name parameter.

Related issues/PRs

• https://github.com/OpenAPITools/openapi-generator/issues/1302
• https://github.com/OpenAPITools/openapi-generator/issues/1110
• https://github.com/OpenAPITools/openapi-generator/issues/2722

Suggest a fix

Looks like we just need to remove the use of packagePath from toModelImport