Support for configuring VoyageAI output dimensions

[michael-pont]

From https://docs.voyageai.com/reference/embeddings-api, the more recent models support multiple dimensions (such as 2048, 1024 (default), 512, and 256).

I would like to be able to define the number of dimensions for collections using voyage ai embeddings

References https://github.com/weaviate/weaviate/issues/8311