PREFLIGHT_TRANSCRIPT/INTERIM_TRANSCRIPT should clear false interruption timer

Bug Description

Currently, the false-interruption timer doesn't get cleared until a turn is committed, which can often longer than the false interruption timeout in some scenarios.

Expected Behavior

A PREFLIGHT_TRANSCRIPT/INTERIM_TRANSCRIPT event should clear the false interruption timer.

Reproduction Steps

Interrupt the AI, stop in the middle of a sentence, and pause.
This causes the interim transcript to get totally lost, and the AI resumes.

Operating System

macOS Tahoe

Models Used

Deepgram FLux

Package Versions

livekit-agents==1.7.1