websocket exceeds message length

[beasteers]

Sometimes when querying multiple streams, especially multiple videos, the message size of each payload can be too big when it tries to send everything at once and it will crash the websocket.

To fix that, maybe we want to send one stream per message instead. Although that may also mean we want to add some helper utilities to ptgctl to handle synchronizing the data streams (knowing when the next batch of streams has come in and we should begin processing or if we should wait for more messages).

relevant lines
https://github.com/VIDA-NYU/ptg-api-server/blob/main/app/routers/data.py#L151-L153