Add percentage as an alternative y-axis display for the exposure duration plot

[LittleBeannie]

The current interactive exposure duration table shows "Number of patients" on the y-axis. In addition to the counts, could we also include percentages? Specifically, can we implement a feature such as a radio button that allows users to choose between "display counts" and "display percentages"?

[fukuhiro2023]

Currently, a user can select the y-axis by the display argument. If display = "prop" is specified, the percentage of participants can be displayed, while diplay = "n" (by default) displays the number of participants.