ESQL: Remote ENRICH needs to check for upstream FORKs #131445
Description
Looking at Enrich#postAnalysisPlanVerification, there doesn't seem to be anything that prevents a FORK upstream from remote-only ENRICH; however, I believe FORK requires merging on the coordinator, so a remote-only ENRICH doesn't make sense.
Cc @smalyshev , @ioanatia