fix: convert webm to wav for OpenAI transcription endpoint

backend/open_webui/routers/audio.py

@@ -83,6 +83,8 @@ def audio_needs_conversion(file_path):
         return "mp4"
     elif info.get("format_name") == "ogg":
         return "ogg"
+    elif info.get("format_name") == "matroska,webm":
+        return "webm"
     return None