[v1.14] Add `progressTrace`, `writeChannelCongestion`, and `internalDatabaseSizes` to batches `stats`

[Strift]

This issue follows the changes related to Meilisearch v1.14.0 mega issue.

Description

Add progressTrace, writeChannelCongestion, and internalDatabaseSizes to batches stats.

[!warning] Do not type the fields inside those objects. The fields can change in a breaking way.

For more context, see the related issues in Meilisearch:

• Progress trace & write channel congestion: https://github.com/meilisearch/meilisearch/issues/5359
• Internal database size: https://github.com/meilisearch/meilisearch/issues/5463