fix(sarvam): default TTS retries to zero while honoring explicit conn options

[dhruvladia-sarvam]

Summary

• Sarvam TTS no longer inherits LiveKit's default max_retry=3 when AgentSession passes DEFAULT_API_CONNECT_OPTIONS.
• Failed synthesize() / stream() calls now fail immediately by default instead of replaying the request.
• Callers can still opt into retries (or change timeout/interval) by passing a constructed APIConnectOptions.

Test plan

• Start an agent with Sarvam TTS and no custom tts_conn_options; confirm a failed TTS request is not retried.
• Pass SessionConnectOptions(tts_conn_options=APIConnectOptions(max_retry=N, ...)) and confirm N retries are used.
• Confirm timeout and retry_interval from an explicit APIConnectOptions are preserved.

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.