[BUG][APEX] generated models duplicate property map for each transformed property

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• 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

Schemas, requests, or responses, with two or more properties defined which are transformed this_id -> thisId cause APEX models generated to be invalid. For each transformed property the resulting class will have n x private static final Map<String, String> propertyMappings and public Map<String, String> getPropertyMappings() defined

openapi-generator version

7.17.0

OpenAPI declaration file content or url

{
  "openapi": "3.0.3",
  "info": {
    "title": "test API",
    "version": "65.0"
  },
  "paths": {

  },
  "components": {
    "schemas": {
      "RecordDetails": {
        "type": "object",
        "title": "RecordDetails",
        "properties": {
          "record_id": {
            "type": "integer",
            "title": "Record Id",
            "description": "Record identifier"
          },
          "name": {
            "type": "string",
            "title": "Name",
            "description": "Record name"
          },
          "other_id": {
            "type": "integer",
            "title": "Other Id",
            "description": "Other identifier"
          }
        },
        "required": [],
        "additionalProperties": false
      }
    }
  }
}

Results

/*
 * test API
 * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
 *
 * The version of the OpenAPI document: 65.0
 * 
 *
 * NOTE: This class is auto generated by the OAS code generator program.
 * https://github.com/OpenAPITools/openapi-generator
 * Do not edit the class manually.
 */

/**
 * OASRecordDetails
 */
public class OASRecordDetails {
    /**
     * Record identifier
     * @return recordId
     */
    public Integer recordId { get; set; }

    /**
     * Record name
     * @return name
     */
    public String name { get; set; }

    /**
     * Other identifier
     * @return otherId
     */
    public Integer otherId { get; set; }

    private static final Map<String, String> propertyMappings = new Map<String, String>{
        'record_id' => 'recordId',
        'other_id' => 'otherId'
    };

    public Map<String, String> getPropertyMappings() {
        return propertyMappings;
    }

    private static final Map<String, String> propertyMappings = new Map<String, String>{
        'record_id' => 'recordId',
        'other_id' => 'otherId'
    };

    public Map<String, String> getPropertyMappings() {
        return propertyMappings;
    }

    public static OASRecordDetails getExample() {
        OASRecordDetails recordDetails = new OASRecordDetails();
          recordDetails.recordId = 0;
          recordDetails.name = '';
          recordDetails.otherId = 0;
        return recordDetails;
    }

    public Boolean equals(Object obj) {
        if (obj instanceof OASRecordDetails) {           
            OASRecordDetails recordDetails = (OASRecordDetails) obj;
            return this.recordId == recordDetails.recordId
                && this.name == recordDetails.name
                && this.otherId == recordDetails.otherId;
        }
        return false;
    }

    public Integer hashCode() {
        Integer hashCode = 43;
        hashCode = (17 * hashCode) + (recordId == null ? 0 : System.hashCode(recordId));
        hashCode = (17 * hashCode) + (name == null ? 0 : System.hashCode(name));
        hashCode = (17 * hashCode) + (otherId == null ? 0 : System.hashCode(otherId));
        return hashCode;
    }
}

Expected

/*
 * test API
 * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
 *
 * The version of the OpenAPI document: 65.0
 * 
 *
 * NOTE: This class is auto generated by the OAS code generator program.
 * https://github.com/OpenAPITools/openapi-generator
 * Do not edit the class manually.
 */

/**
 * OASRecordDetails
 */
public class OASRecordDetails {
    /**
     * Record identifier
     * @return recordId
     */
    public Integer recordId { get; set; }

    /**
     * Record name
     * @return name
     */
    public String name { get; set; }

    /**
     * Other identifier
     * @return otherId
     */
    public Integer otherId { get; set; }

    private static final Map<String, String> propertyMappings = new Map<String, String>{
        'record_id' => 'recordId',
        'other_id' => 'otherId'
    };

    public Map<String, String> getPropertyMappings() {
        return propertyMappings;
    }

    public static OASRecordDetails getExample() {
        OASRecordDetails recordDetails = new OASRecordDetails();
          recordDetails.recordId = 0;
          recordDetails.name = '';
          recordDetails.otherId = 0;
        return recordDetails;
    }

    public Boolean equals(Object obj) {
        if (obj instanceof OASRecordDetails) {           
            OASRecordDetails recordDetails = (OASRecordDetails) obj;
            return this.recordId == recordDetails.recordId
                && this.name == recordDetails.name
                && this.otherId == recordDetails.otherId;
        }
        return false;
    }

    public Integer hashCode() {
        Integer hashCode = 43;
        hashCode = (17 * hashCode) + (recordId == null ? 0 : System.hashCode(recordId));
        hashCode = (17 * hashCode) + (name == null ? 0 : System.hashCode(name));
        hashCode = (17 * hashCode) + (otherId == null ? 0 : System.hashCode(otherId));
        return hashCode;
    }
}

Generation Details

yarn openapi-generator-cli generate -g apex -o output/test -i 

Steps to reproduce

1. create openapi.json with the provided spec
2. Run yarn openapi-generator-cli generate -g apex -o output/test -i {yourpathtofile}

Related issues/PRs

Suggest a fix

I believe the logic in the ApexCodegen is causing duplicate maps,

https://github.com/OpenAPITools/openapi-generator/blob/1e3f6d0ed94c64c08557fc2778f980d407d83453/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractApexCodegen.java#L440

Start in modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractApexCodegen.java around line 440, then reproduce with the supplied OpenAPI declaration and the yarn openapi-generator-cli command. Done means the generated Apex model contains one propertyMappings map and one getPropertyMappings method, even when multiple properties are transformed.