3266: Improve the way we receive the documents payload- serde multiple ndjson fix r=curquiza a=jiangbo212
# Pull Request
## Related issue
Fixes#3037
## Related PR
#3164
## What does this PR do?
Sorry, This PR is mainly to fix the problems caused by my previously provided PR #3164. It causes multiple ndjson data deserialization failures
- Fix serde multiple ndjson data failures and add test to it
- Fix serde jsonarray error and againest serde it use `from_slice`. only use `from_slice` when serde error category is `data`, it indicate json data is a single json.
## 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: jiangbo212 <peiyaoliukuan@126.com>
