fix bug and optimize keepalive

[lauridsdev]

In some cases, connect is called before start, or the connection is already established. This can result in the “old” connection leading to a “received 1008 (policy violation)” error from ElevenLabs 20 seconds after start, due to no text being sent.

Also ensures that the keep-alive message is only sent when necessary.

[aconchillo]

Thank you so much! And sorry for the delay! :pray:

[markbackman]

Apologies for letting this go for so long. These issues have since been resolved, so I'm closing out this contribution.