Return Patient ID upon clicking on a circle in scatterplot for patient profiles

[pburnsdata]

This will allow this to integrate with patient profiles @jwildfire

from SafetyGraphics: https://github.com/SafetyGraphics/safetyGraphics/blob/b34bca0f6d7f7f94bf11cde2adeb5069b56656ee/R/mod_safetyGraphicsServer.R#L66

from SafetyCharts: https://github.com/SafetyGraphics/safetyCharts/blob/dev/inst/htmlwidgets/lib/addClickListener.js

[pburnsdata]

@jwildfire any examples elsewhere of how this is done (is it called pt_id etc?)- guessing just a return on the server module, but maybe we could borrow from something if you've done it for another aggregate chart