Holding Streams Open with Stream KeepAlive

Stream KeepAlive is a feature that allows developers to keep DG streams open without sending any data. This can be useful in various scenarios, such as opening a websocket before it's needed or stopping the transmission of unwanted transcribed data. The system previously closed connections if no audio data was sent for a couple of seconds, which could be frustrating for developers. To address this issue, users can now send a KeepAlive message to keep the stream open for an additional 60 seconds. This feature aims to improve the development experience and provide more flexibility in managing websocket connections.