4938: Remove default embedder r=ManyTheFish a=dureuill
# Pull Request
## Related issue
Fixes#4738
## What does this PR do?
[See public usage](https://meilisearch.notion.site/v1-11-AI-search-changes-0e37727193884a70999f254fa953ce6e#1044b06b651f80edb9d4ef6dc367bad0)
- Remove `hybrid.embedder` boolean from analytics because embedder is now mandatory and so the boolean would always be `true`
- Rework search kind so that a search without query but with vector is a vector search regardless of (non-zero) semantic ratio
Co-authored-by: Louis Dureuil <louis@meilisearch.com>
