Return ingest byte stats even when 0-valued

[parkertimmins]

Change the ingest byte stats to always be returned whether or not they have a value of 0. Add human readable form of byte stats. Update docs to reflect changes.

Related to https://github.com/elastic/elasticsearch/pull/107240

[github-actions[bot]]

Documentation preview:

• ✨ Changed pages

[elasticsearchmachine]

Hi @parkertimmins, I've created a changelog YAML for you.

[elasticsearchmachine]

Pinging @elastic/es-data-management (Team:Data Management)