Revert "Configure @opensearch.internal as custom Javadoc tag"

This reverts commit 2077d76.

Signed-off-by: Kartik Ganesh <gkart@amazon.com>

Author: kartg

server/build.gradle

@@ -35,12 +35,6 @@ apply plugin: 'nebula.optional-base'
 apply plugin: 'opensearch.publish'
 apply plugin: 'opensearch.internal-cluster-test'
 
-javadoc {
-  options.tags = [
-    "opensearch.internal"
-  ]
-}
-
 publishing {
   publications {
     nebula {