I am developing an ArcGIS Pro Add-In (not ArcGIS Pro Configuration). In my Add-in project, is there any way to get notified and execute some code when the user opens up the ArcGIS Pro application? I know that there is a class called ApplicationStartupEvent, but in order to use this class I need to subscribe to it first without having the user click on something in the ribbon. Is this possible? Or is it true that using ArcGIS Pro Configuration is the only way to achieve this?