R1:45c3aaeb269e

Attempt to make dropdown item actions more consistent

Summary:
See D17210. Currently, this handler needs to be installed on each menu that doesn't build with the default behavior.

Rather than copy-pasting it to the user menu, try to make it a default behavior. This adds a new rule: don't close the menu if the item is a dynamic item built in JS with PHUIXActionView.

This allows dynamic items to control the menu themselves, while giving static items the desired default behavior.

Test Plan:
- Opened…