#33708 introduced a strict deprecation mode that makes a REST request
fail if there is a warning header in the response returned by
Elasticsearch (usually a deprecation message signaling that a feature
or a field has been deprecated).
This change adds the strict deprecation mode into the REST integration
tests, and makes the tests fail if a deprecated feature is used. Also
any test using a deprecated feature has been modified to pass the build.
The YAML integration tests already analyzed HTTP warnings so they do
not use this mode, keeping their "expected vs actual" behavior.
d5ad3de42e