standardize reward volume calculation in summary figures

[ryyesterday]

The amount of water for a given session on the mouse summary figure does not agree with the associated value on the daily summary figure.

It looks like the daily summary figure is showing a plot of the cumulative_volume key and reporting the max value in the table https://github.com/AllenInstitute/visual_behavior_analysis/blob/master/visual_behavior/visualization/extended_trials/daily.py#L40

The mouse summary is using the total_water key from the summary dataframe. total_water per trial is the number of rewards multiplied by the reward volume.
https://github.com/AllenInstitute/visual_behavior_analysis/blob/master/visual_behavior/visualization/extended_trials/mouse.py#L122 https://github.com/AllenInstitute/visual_behavior_analysis/blob/master/visual_behavior/change_detection/trials/session_metrics.py#L79