Address review comment

Author: snitish

pandas/core/_numba/kernels/var_.py

@@ -196,7 +196,6 @@ def grouped_var(
 
         if not skipna and np.isnan(val):
             output[lab] = np.nan
-            nobs_arr[lab] += 1
             comp_arr[lab] = np.nan
             consecutive_counts[lab] = 1
             prev_vals[lab] = np.nan