add a new IAM example to support S3 topic

Author: scmacdon

.doc_gen/metadata/iam_metadata.yaml

@@ -1709,9 +1709,6 @@ iam_CreateRole:
             - description: Creates an IAM role.
               snippet_tags:
                 - iam.java2.create_role.main
-            - description: Creates an IAM role with the necessary permissions to perform object lock operations on an S3 bucket.
-              snippet_tags:
-                - iam.java2.s3_role.main
     PHP:
       versions:
         - sdk_version: 3