Use full customer build file in downgrade prevention test

Expand dontDowngradeKotlinDslSharedVariable to use the complete
customer build file from customer-requests#1809, including all 5
Kotlin plugins, Spring Boot, dependency-management, application
plugin, dependencies block, and toolchain configuration.

Author: MBoegers

rewrite-gradle/src/test/java/org/openrewrite/gradle/plugins/UpgradePluginVersionTest.java

@@ -485,7 +485,79 @@ void dontDowngradeKotlinDslSharedVariable() {
                   val kotlinVersion = "1.8.21"
                   id("org.jetbrains.kotlin.jvm") version kotlinVersion
                   id("org.jetbrains.kotlin.plugin.allopen") version kotlinVersion
+                  id("org.jetbrains.kotlin.plugin.noarg") version kotlinVersion
                   id("org.jetbrains.kotlin.plugin.spring") version kotlinVersion
+                  id("org.jetbrains.kotlin.plugin.jpa") version kotlinVersion
+                  id("org.springframework.boot") version "3.2.1"
+                  id("io.spring.dependency-management") version "1.1.4"
+                  id("com.adarshr.test-logger") version "4.0.0"
+                  application
+                  jacoco
+              }
+
+              application {
+                  mainClass.set("com.example.ApplicationKt")
+              }
+
+              repositories {
+                  mavenCentral()
+              }
+
+              dependencies {
+                  implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
+                  implementation("org.jetbrains.kotlin:kotlin-reflect")
+                  implementation("org.jetbrains.kotlinx", "kotlinx-coroutines-core", "1.1.1")
+                  implementation("org.springframework.boot", "spring-boot-starter-web")
+                  implementation("org.springframework.boot", "spring-boot-starter-security")
+                  implementation("org.springframework.boot", "spring-boot-starter-data-jpa")
+                  implementation("com.mysql", "mysql-connector-j")
+                  implementation("com.zaxxer", "HikariCP")
+                  implementation("org.flywaydb", "flyway-core")
+                  implementation("org.flywaydb", "flyway-mysql")
+                  implementation("org.hibernate.orm", "hibernate-envers")
+                  implementation("io.github.microutils", "kotlin-logging", "3.0.4")
+                  implementation("org.springframework.boot", "spring-boot-starter-logging")
+                  constraints {
+                      implementation("ch.qos.logback", "logback-classic", "1.4.14") {
+                          because("CVE-2023-6378 vulnerability")
+                      }
+                      implementation("ch.qos.logback", "logback-core", "1.4.14") {
+                          because("CVE-2023-6378 vulnerability")
+                      }
+                  }
+                  implementation("net.logstash.logback", "logstash-logback-encoder", "7.2")
+                  implementation("javax.mail", "mail", "1.4.7")
+                  implementation("org.springdoc", "springdoc-openapi-starter-webmvc-ui", "2.3.0")
+                  implementation("com.fasterxml.jackson.core", "jackson-core")
+                  implementation("com.fasterxml.jackson.core", "jackson-databind")
+                  implementation("com.fasterxml.jackson.core", "jackson-annotations")
+                  implementation("com.fasterxml.jackson.module", "jackson-module-kotlin")
+                  implementation("com.fasterxml.jackson.datatype", "jackson-datatype-jsr310")
+                  implementation("com.squareup.okhttp3", "okhttp", "3.9.0")
+                  implementation("com.cronutils", "cron-utils", "9.2.1")
+                  testImplementation("org.springframework.boot", "spring-boot-starter-test") {
+                      exclude(module = "mockito-core")
+                  }
+                  testImplementation("org.mockito", "mockito-core", "2.8.9")
+                  testRuntimeOnly("com.h2database", "h2")
+                  val jupiterVersion = "5.10.2"
+                  testImplementation("org.junit.jupiter", "junit-jupiter-api", jupiterVersion)
+                  testRuntimeOnly("org.junit.jupiter", "junit-jupiter-engine", jupiterVersion)
+                  testImplementation("org.junit.jupiter", "junit-jupiter-params", jupiterVersion)
+                  testRuntimeOnly("org.junit.vintage", "junit-vintage-engine", jupiterVersion)
+                  implementation("org.springframework.vault:spring-vault-core:3.1.1")
+              }
+
+              java {
+                  toolchain {
+                      languageVersion.set(JavaLanguageVersion.of(17))
+                  }
+              }
+
+              tasks.withType<Test> {
+                  useJUnitPlatform {
+                      includeEngines = setOf("junit-jupiter", "spek")
+                  }
               }
               """
           )