Streaming in wasm doesn’t work

[irevoire]

Currently, when streaming documents in wasm, we actually collect everything in RAM before sending it: https://github.com/meilisearch/meilisearch-rust/blob/437649f05264499de8e0e123e310eeee459bace5/src/reqwest.rs#L80-L100

This is because reqwest doesn’t provide the wrap_stream method, see: https://github.com/seanmonstar/reqwest/issues/2248