SolrJ's LukeRequest should support "includeIndexFieldFlags"

SOLR-7799 introduces the query-param flag "includeIndexFieldFlags", which tells Solr that the index flags aren't needed and can be skipped. Fetching these flags takes some time, so specifying includeIndexFieldFlags=false on requests can save some time for if users don't need that information and have collections with a lot of fields.

Support for this flag was never added to the SolrJ class used to trigger requests to Luke though. It's a pain to use the flag in SolrJ as LukeRequest is currently written.