Fix: Improve the field location reporting in config errors (#4511)

Author: izeigerman

sqlmesh/utils/pydantic.py

@@ -221,7 +221,8 @@ def _formatted_validation_errors(error: pydantic.ValidationError) -> t.List[str]
     for e in error.errors():
         msg = e["msg"]
         loc: t.Optional[t.Tuple] = e.get("loc")
-        result.append(f"Invalid field '{loc[0]}':\n    {msg}" if loc else msg)
+        loc_str = ".".join(loc) if loc else None
+        result.append(f"Invalid field '{loc_str}':\n    {msg}" if loc_str else msg)
     return result