[Build] Add jUnit dependencies in testApiJUnit5 to the implementation configuration

Adding these dependencies to the `api` configuration pollutes classpath for each dependant modules even if it doesn't need them. Instead, the dependencies should be declared more granularly if they're required
#KTI-1349 In Progress

libraries/examples/scripting/jvm-simple-script/host/build.gradle.kts

@@ -8,7 +8,7 @@ dependencies {
     api(project(":kotlin-scripting-jvm-host-unshaded"))
     testRuntimeOnly(project(":kotlin-compiler"))
     testRuntimeOnly(project(":kotlin-scripting-compiler"))
-    testApi(libs.junit4)
+    testImplementation(libs.junit4)
 }
 
 sourceSets {