[8.19] [ML] Custom service add support for input_type, top_n, and return_documents (#129441)#129860

elasticsearchmachine merged 2 commits intoelastic:8.19elastic/elasticsearch:8.19from

jonathan-buttner:backport/8.19/pr-129441jonathan-buttner/elasticsearch:backport/8.19/pr-129441Copy head branch name to clipboard