3269: Simplify primary key inference r=dureuill a=dureuill
# Pull Request
## Related issue
Related to https://github.com/meilisearch/meilisearch/issues/3233
## What does this PR do?
- Integrates https://github.com/meilisearch/milli/pull/752 in meilisearch
- Remove `Serialize` and `Deserialize` from `error::Code` as it is unused.
- No longer filter on `milli` logs when `--log-level` is "info".
- `milli` only has the newly-added inference log at the `info` level (from greping `info` in the codebase)
- the default value for `--log-level` is "INFO" and not "info" since `v0.30` so the filter is not active by default.
- updates milli to v0.38.0
## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?
Thank you so much for contributing to Meilisearch!
Co-authored-by: Louis Dureuil <louis@meilisearch.com>
