Investigate potential deprecation warning leak #143884
Description
Recently (#141877), we deprecated the default_metric of the aggregate_metric_double field type. As a result, elasticsearch adds a deprecation warning to any request that is using this configuration.
We have adjusted tests to allow this warning. Unfortunately, it seems like these warnings some times leak to other requests too. For example, in the following logs we see an index create request that is not using an aggregate_metric_double at all is also returning the warning header in certain scenarios:
[2026-03-03T12:11:44,927][WARN ][o.e.c.RestClient ][testTsIndexConflictingTypes] request [PUT http://[::1]:36637/metrics-long] returned 1 warnings: [299 Elasticsearch-9.4.0-bca3093cd0619c6871cfa5d1cad2e839fcfbdc9b "Parameter [default_metric] is deprecated and will be removed in a future version"]
[2026-03-03T12:11:44,933][ERROR][o.e.x.e.q.r.FieldExtractorTestCase][testTsIndexConflictingTypes] Received warning when creating index [metrics-long] with mapping [{metrics-long={mappings={_data_stream_timestamp={enabled=true}, properties={@timestamp={type=date}, metric={properties={name={time_series_dimension=true, type=keyword}, value={time_series_metric=gauge, type=long}}}}}}}]