Fix the parse_cors function to be consistent for both empty string and empty list

Author: rolkotaki

backend/app/core/config.py

@@ -18,6 +18,8 @@
 
 def parse_cors(v: Any) -> list[str] | str:
     if isinstance(v, str) and not v.startswith("["):
+        if not v.strip():
+            return []
         return [i.strip() for i in v.split(",")]
     elif isinstance(v, list | str):
         return v