Updated dynamic mapper section
Updated dynamic mapper section

Similar to https://github.com/elastic/elasticsearch/pull/21551, removing reference to setting dynamic mapper at the node level.
strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test