[Backport 2.x] Add getMetadataFields to MapperService (#13819) · opensearch-project/OpenSearch@4cb9129

HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK is set: not checking for outdated dependents or dependents with broken linkage!

Treating docker as a formula. For the cask, use homebrew/cask/docker or specify the `--cask` flag.

HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK is set: not checking for outdated dependents or dependents with broken linkage!