replaced model names with CONSTANT

Author: minh-hoque

examples/Speech_transcription_methods.ipynb

@@ -412,15 +412,15 @@
     "        \"session\": {\n",
     "            \"input_audio_format\": \"pcm16\",\n",
     "            \"turn_detection\": {\"type\": \"server_vad\", \"threshold\": vad},\n",
-    "            \"input_audio_transcription\": {\"model\": MODEL_NAME},\n",
+    "            \"input_audio_transcription\": {\"model\": model},\n",
     "        },\n",
     "    }\n",
     "\n",
     "async def transcribe_audio_async(\n",
     "    wav_path,\n",
     "    api_key,\n",
     "    *,\n",
-    "    model: str = \"gpt-4o-transcribe\",\n",
+    "    model: str = MODEL_NAME,\n",
     "    chunk: int = CHUNK_SAMPLES,\n",
     ") -> str:\n",
     "    pcm = load_and_resample(wav_path)\n",