Description

When using the Gemini Live backend, there is noticeable end-of-speech latency compared to competitors. Additionally, releasing the spacebar immediately after finishing a sentence often causes the last sentence to not appear (buffer cutoff issue). Actually looks like this is also an issue with the local models now

Requirements

• Investigate the buffer handling and connection teardown in the GeminiLiveTranscriptionProvider.
• Ensure trailing audio is fully processed and returned before closing the transcription stream.

Epic: #24175