fix: multiply the embedding list by their dimension to get the real size

[maximaxft]

The current is not working, I got the error:
self._index.add_items(data=embeddings, ids=ids, num_threads=self.config.num_threads)
RuntimeError: The number of elements exceeds the specified limit
We need to multiply each element of the embedding list by their side (which is constant: self.embedding_dim) in the line 56 :
if self.size + len(embeddings)*self.embedding_dim >= self.max_size:

[liukidar]

Mmmh, size, max_size and embeddings are all referring to each embedding vector as a single entity, so I am not sure multiplying by the embedding_dim is the right solution, instead, there may be a bug hiding somewhere else.