fix(kotlin-spring): register useJackson3 CLI option and use Gradle 8.14 for SB4

- Add addSwitch for useJackson3 in KotlinSpringServerCodegen so it
  appears in auto-generated docs
- Update gradle-wrapper.properties.mustache templates to use Gradle 8.14
  when useSpringBoot4 is enabled (required minimum for Spring Boot 4)

Author: yonatankarp

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinSpringServerCodegen.java

@@ -256,6 +256,7 @@ public KotlinSpringServerCodegen() {
                 " (contexts) added to single project.", beanQualifiers);
         addSwitch(USE_SPRING_BOOT3, "Generate code and provide dependencies for use with Spring Boot ≥ 3 (use jakarta instead of javax in imports). Enabling this option will also enable `useJakartaEe`.", useSpringBoot3);
         addSwitch(USE_SPRING_BOOT4, "Generate code and provide dependencies for use with Spring Boot 4.x. Enabling this option will also enable `useJakartaEe`.", useSpringBoot4);
+        addSwitch(USE_JACKSON_3, "Use Jackson 3 dependencies (tools.jackson package). Only available with `useSpringBoot4`. Incompatible with `openApiNullable`.", useJackson3);
         addSwitch(USE_FLOW_FOR_ARRAY_RETURN_TYPE, "Whether to use Flow for array/collection return types when reactive is enabled. If false, will use List instead.", useFlowForArrayReturnType);
         addSwitch(INCLUDE_HTTP_REQUEST_CONTEXT, "Whether to include HttpServletRequest (blocking) or ServerWebExchange (reactive) as additional parameter in generated methods.", includeHttpRequestContext);
         addSwitch(USE_RESPONSE_ENTITY,

modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/gradle-wrapper.properties.mustache

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
+{{#useSpringBoot4}}distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip{{/useSpringBoot4}}{{^useSpringBoot4}}distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip{{/useSpringBoot4}}
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-cloud/gradle-wrapper.properties.mustache

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
+{{#useSpringBoot4}}distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip{{/useSpringBoot4}}{{^useSpringBoot4}}distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip{{/useSpringBoot4}}
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-declarative-http-interface/gradle-wrapper.properties.mustache

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
+{{#useSpringBoot4}}distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip{{/useSpringBoot4}}{{^useSpringBoot4}}distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip{{/useSpringBoot4}}
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME