Removing Levels Index Variable Within Atomic Data Preperation (#1957)

* Removed Levels Index Filter

* Test

tardis/io/atom_data/base.py

@@ -330,10 +330,6 @@ def prepare_atom_data(
 
         self.nlte_species = nlte_species
 
-        self.levels_index = pd.Series(
-            np.arange(len(self.levels), dtype=int), index=self.levels.index
-        )
-
         # cutting levels_lines
         self.lines = self.lines[
             self.lines.index.isin(
@@ -352,22 +348,10 @@ def prepare_atom_data(
             "level_number_upper"
         )
 
-        self.lines_lower2level_idx = (
-            self.levels_index.loc[tmp_lines_lower2level_idx]
-            .astype(np.int64)
-            .values
-        )
-
         tmp_lines_upper2level_idx = self.lines.index.droplevel(
             "level_number_lower"
         )
 
-        self.lines_upper2level_idx = (
-            self.levels_index.loc[tmp_lines_upper2level_idx]
-            .astype(np.int64)
-            .values
-        )
-
         if (
             self.macro_atom_data_all is not None
             and not line_interaction_type == "scatter"