Fix missing engine field in benchmark.csv.

benchmark.csv

@@ -9,5 +9,5 @@ faster-whisper,ivrit-ai/whisper-large-v3-turbo-ct2,0.067,0.077,0.245,0.209,0.100
 amazon-transcribe,stream,0.081,0.090,0.287,0.200,0.131
 faster-whisper,large-v3,0.096,0.094,0.262,0.231,0.134
 google-speech,google-speech,0.212,0.189,0.385,0.380,0.292
-openai-gpt4o-transcribe,0.074,0.109,0.210,0.169,0.394
-openai-gpt4o-mini-transcribe,0.093,0.150,0.300,0.237,0.468
+openai,gpt4o-transcribe,0.074,0.109,0.210,0.169,0.394
+openai,gpt4o-mini-transcribe,0.093,0.150,0.300,0.237,0.468