track_total_hits of elasticsearch_api's SearchBody is ignored

[RaphaelMarinier]

Describe the bug
track_total_hits in the Elastic Search API can be specified in two places:

• SearchBody (ES doc)
• SearchQueryParams (ES doc)

However, in Quickwit, SearchBody.track_total_hits is ignored. Only SearchQueryParams.track_total_hits is taken into account.

Expected behavior
Both SearchBody.track_total_hits and SearchQueryParams.track_total_hits should be taken into account there:

quickwit/quickwit/quickwit-serve/src/elasticsearch_api/rest_handler.rs

Line 269 in f37d8b6

let count_hits = match search_params.track_total_hits {

According to this ES doc, if both are specified, the one in SearchQueryParams wins.