Remove jarhell check disablement

JarHell was disabled due to an issue with Kafka where there were
multiple copies of the same class packaged inside of a release and test
distribution jar.  This was resolved with apache/kafka#12407

The Kafka change has been merged, released, and pulled into this
repository so we are removing the workaround to supress jar hell issue
detection.

- Resolves opensearch-project#1938

Signed-off-by: Peter Nied <[email protected]>

build.gradle

@@ -106,8 +106,7 @@ forbiddenApisTest.enabled = false
 filepermissions.enabled = false
 forbiddenPatterns.enabled = false
 testingConventions.enabled = false
-// Conflicts between runtime kafka-clients:x.y.z & testRuntime kafka-clients:x.y.z:test
-jarHell.enabled = false
+jarHell.enabled = true
 tasks.whenTaskAdded {task ->
     if(task.name.contains("forbiddenApisIntegrationTest")) {
         task.enabled = false