[ FEATURE ] Add exit animations

[billnye2]

Is your feature request related to a problem? Please describe.
Hey really cool lib, I'm gonna try using it. Noticed that the enter animations are nice and mimic og shadcn nicely. But also see that exit animations aren't implemented yet, for instance the dropdown menu immediately disappears on exit rather than animating with a fade out. This was tested on the web demo, not sure what mobile side looks like yet. I believe shadcn added exit animations to his lib around a year ago. Wondering if this is on the roadmap?

Great library,
Thanks!

[RWOverdijk]

I'd like to add to this that I see the same with popover. It appears to "flicker". It has an animation (exit fadeOut) but somewhere in the chain it goes wrong.

I think an attempt has been made but perhaps it's just not done yet. I might take a crack at this once I start looking at rn-primitives.