5080: Fix getting a single batch through the GET route r=Kerollmops a=dureuill
# Pull Request
## Related issue
Fixes a bug where getting a single batch does not work
Related to #5070
fix by `@Kerollmops`
Co-authored-by: Louis Dureuil <louis@meilisearch.com>
* Remove unreachable code
* Add `indices` field to `MatchBounds`
For matches inside arrays, this field holds the indices of the array
elements that matched. For example, searching for `cat` inside
`{ "a": ["dog", "cat", "fox"] }` would return `indices: [1]`. For nested
arrays, this contains multiple indices, starting with the one for the
top-most array. For matches in fields without arrays, `indices` is not
serialized (does not exist) to save space.
