Update fixture to include fcst_step_range parameter

Added the `fcst_step_range` parameter to the `mock_calc_nemo_var_ds()`
test fixture. This change ensures alignment with the updated function signature
and fixes test failures.

Author: douglatornell

tests/workers/test_grib_to_netcdf.py

@@ -248,7 +248,14 @@ def _mock_open_dataset(path):
     @pytest.fixture
     def mock_calc_nemo_var_ds(monkeypatch):
         def _mock_calc_nemo_var_ds(
-            msc_var, grib_var, nemo_var, grib_files, full_grid, georef_ds, config
+            msc_var,
+            grib_var,
+            nemo_var,
+            grib_files,
+            fcst_step_range,
+            full_grid,
+            georef_ds,
+            config,
         ):
             pass