[Build] Move JUnit dependencies into the version catalog

The `kotlin-test` dependencies are left untouched as changing them affects publications, thus these versions are independent from the used inside our build
#KTI-1349 In Progress

libraries/tools/kotlin-gradle-plugin/build.gradle.kts

@@ -141,7 +141,7 @@ dependencies {
     testImplementation(projectTests(":kotlin-build-common"))
     testImplementation(project(":kotlin-compiler-runner"))
     testImplementation(project(":kotlin-test:kotlin-test-junit"))
-    testImplementation(commonDependency("junit:junit"))
+    testImplementation(libs.junit4)
     testImplementation(project(":kotlin-gradle-statistics"))
     testImplementation(project(":kotlin-tooling-metadata"))
 }