[BUG][kotlin][jvm-spring-webclient] Query Parameter is created wrong, when using enum with non-default enumPropertyNaming

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

We want to call an API, which has an endpoint with a query parameter, with an enum set of values, e.g. a timeRange of OneWeek, OneMonth or OneYear.
We create the calling API classes via OpenAPIGenerator with generator kotlin and library jvm-spring-webclient and enumPropertyNaming=UPPERCASE.
The enum is created with all values in UPPERCASE and the original value is set in a variable called value.

    enum class TimeRangeGetExample(val value: kotlin.String) {
        @JsonProperty(value = "OneWeek") ONE_WEEK("OneWeek"),
        @JsonProperty(value = "OneMonth") ONE_MONTH("OneMonth"),
        @JsonProperty(value = "OneYear") ONE_YEAR("OneYear")
    }

But when calling via the created API, the UPPERCASE name of the enum value is used instead of the original value written in the spec.

Expected:
example.com/example?timeRange=OneWeek

Actual:
example.com/example?timeRange=ONE_WEEK

The created API class contains following code:

    fun getExampleRequestConfig(timeRange: TimeRangeGetExample) : RequestConfig<Unit> {
        val localVariableBody = null
        val localVariableQuery = mutableMapOf<kotlin.String, kotlin.collections.List<kotlin.String>>()
            .apply {
                put("timeRange", listOf(timeRange.toString()))
            }

Instead of calling toString, the variable value has to be used

    fun getExampleRequestConfig(timeRange: TimeRangeGetExample) : RequestConfig<Unit> {
        val localVariableBody = null
        val localVariableQuery = mutableMapOf<kotlin.String, kotlin.collections.List<kotlin.String>>()
            .apply {
                put("timeRange", listOf(timeRange.value))
            }

or the toString method has to be overwritten with:

override fun toString() = value

openapi-generator version

7.14.0

OpenAPI declaration file content or url

swagger: '2.0'
info:
  version: v1
  title: Test.Api
host: example.com
schemes:
  - https
paths:
  /example:
    get:
      operationId: getExample
      consumes: [ ]
      produces:
        - application/json
        - text/json
      parameters:
        - name: timeRange
          in: query
          required: true
          type: string
          enum:
            - OneWeek
            - OneMonth
            - OneYear
      responses:
        '200':
          description: OK

Generation Details

Maven Plugin

      <plugin>
        <groupId>org.openapitools</groupId>
        <artifactId>openapi-generator-maven-plugin</artifactId>
        <version>7.14.0</version>
        <configuration>
          <generatorName>kotlin</generatorName>
          <library>jvm-spring-webclient</library>
          <configOptions>
            <sourceFolder>src/main/kotlin</sourceFolder>
            <serializationLibrary>jackson</serializationLibrary>
            <enumPropertyNaming>UPPERCASE</enumPropertyNaming>
            <useSpringBoot3>true</useSpringBoot3>
            <omitGradlePluginVersions>true</omitGradlePluginVersions>
            <omitGradleWrapper>true</omitGradleWrapper>
          </configOptions>
        </configuration>
        <executions>
          <execution>
            <id>example</id>
            <goals>
              <goal>generate</goal>
            </goals>
            <configuration>
              <output>${project.build.directory}/generated-sources/example</output>
              <inputSpec>${project.basedir}/src/main/resources/example/swagger.yml</inputSpec>
              <apiPackage>${project.groupId}.example.client.api</apiPackage>
              <modelPackage>${project.groupId}.example.client.dto</modelPackage>
              <packageName>${project.groupId}.example.client.handler</packageName>
            </configuration>
          </execution>
        </executions>
      </plugin>

Steps to reproduce

Use the generated API class to call the API endpoint. This will fail, because the query parameter will be created wrong.

Related issues/PRs

https://github.com/openapitools/openapi-generator/issues/21564 seems very similar, but is a different generator and library

Start with the Kotlin generator's jvm-spring-webclient output for getExampleRequestConfig and reproduce the issue using the supplied Swagger definition and Maven configuration. Check how the generated query parameter serializes the TimeRangeGetExample enum when enumPropertyNaming=UPPERCASE. Done means the generated request uses the original enum value, producing timeRange=OneWeek rather than timeRange=ONE_WEEK.