fix default ovv field

Author: MyPyDavid

src/raman_fitting/processing/spectrum_constructor.py

@@ -40,7 +40,7 @@ class SpectrumDataLoader:
     file: Path = field(default=Path(Path.cwd().joinpath("empty.txt")))
     spectrum_length: int = field(default=0, init=False)
     info: Dict = field(default_factory=dict, repr=False)
-    ovv: pd.DataFrame = field(default_factory=pd.DataFrame(), repr=False)
+    ovv: pd.DataFrame = field(default_factory=pd.DataFrame, repr=False)
     run_kwargs: Dict = field(default_factory=dict, repr=False)
 
     def __post_init__(self):