Fix Parameter Sensitivity Plot Layout (facebook#3109)

Summary:
Pull Request resolved: facebook#3109

As titled, fix parameter sensitivity plot layout.
1) Makes sure the height is enough to show all parameters
2) Shows the title of the plot

sample sweeps with weird sensitivity plot display: f666814066, f666666748, f666034938

Reviewed By: Balandat

Differential Revision: D66395421

fbshipit-source-id: 861c5888a1b07cb4a1c9b5f1684e1366ba27ed78

ax/plot/feature_importances.py

@@ -244,10 +244,11 @@ def plot_feature_importance_by_feature_plotly(
     longest_label = max(len(f) for f in features)
     longest_metric = max(len(m) for m in sensitivity_values.keys())
     layout = go.Layout(
-        height=len(features) * 20,
+        height=200 + len(features) * 20,
         width=10 * longest_label + max(10 * longest_metric, 400),
         hovermode="closest",
         annotations=compose_annotation(caption=caption),
+        title=f"Parameter Sensitivity by {importance_measure}",
     )
 
     if relative: