[plotting] fixed typo

plotting.py

@@ -347,8 +347,8 @@ def figure_weight_study(
 def figure_multihist(data, columns=None):
     fig, ax = plt.subplots()
     df = pd.DataFrame(np.reshape(data, (data.shape[0], -1)), columns=columns)
-    with warnings.simplefilter("ignore"):  # temporary fix outdated pandas
-        df.hist(figsize=(20, 20))
+    warnings.simplefilter("ignore")  # temporary fix outdated pandas
+    df.hist(figsize=(20, 20))
     fig.tight_layout()
     return fig