[BUG][JAVA] APIClient.mustache template for apache-httplient library unnecessarily verifies if method allows request body

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

Validation code here https://github.com/OpenAPITools/openapi-generator/blob/cf303d4e034ce9d8eb194fb4e37a1f3409814cf9/modules/openapi-generator/src/main/resources/Java/libraries/apache-httpclient/ApiClient.mustache#L1096 prevents me from sending GET request with body data.

I'm using OpenApi version 3.1.0 which explicitly allows to have request body in GET methods.

openapi-generator version

All

Suggest a fix

Remove this validation and leave it for http library to decide if method can have request body.

Start in modules/openapi-generator/src/main/resources/Java/libraries/apache-httpclient/ApiClient.mustache at the validation around line 1096. Check how the apache-httpclient template handles GET request bodies, then verify that generated clients allow the request body decision to reach the HTTP library without this validation.