[7.x] ILM: Allow `searchable_snapshot` to follow `searchable_snapshot` (#68864)#68972

andreidan merged 7 commits intoelastic:7.xelastic/elasticsearch:7.xfrom

andreidan:backport/7.x-searchable-snapshots-validationandreidan/elasticsearch:backport/7.x-searchable-snapshots-validationCopy head branch name to clipboard