Improvements to parsing of WHISPER_LANGUAGE environment variable (Setting as empty string now equivalent to unsetting/removing WHISPER_LANGUAGE). Resolved crash caused when unset

backend/open_webui/config.py

@@ -2510,7 +2510,7 @@ WHISPER_VAD_FILTER = PersistentConfig(
     os.getenv("WHISPER_VAD_FILTER", "False").lower() == "true",
 )
 
-WHISPER_LANGUAGE = os.getenv("WHISPER_LANGUAGE", None).lower()
+WHISPER_LANGUAGE = os.getenv("WHISPER_LANGUAGE", "").lower() or None
 
 # Add Deepgram configuration
 DEEPGRAM_API_KEY = PersistentConfig(