(deepgram) support in call param updates

### Feature Type Nice to have ### Feature Description On [2026-06-15 Deepgram shipped UpdateListen](https://developers.deepgram.com/changelog/2026/6/15#updatelisten-on-the-fly-listen-configuration), an in-band control message to reconfigure an active Flux session without reconnecting. Tunable fields: eot_threshold, eager_eot_threshold, eot_timeout_ms, keyterms, language_hints — which line up almost 1:1 with what update_options() already exposes. The server acks with ListenUpdated. (Model switching is not supported via UpdateListen.) Request: have update_options() send UpdateListen for the live-tunable fields instead of reconnecting, falling back to a reconnect only for fields that can't be updated in-band (model, sample_rate). This avoids dropping the in-flight turn and the audio gap inherent to the current reconnect. ### Workarounds / Alternatives _No response_ ### Additional Context _No response_