R1:a9a5991f010d

Update project profile image composer for new IconSet code

Summary:
Fixes T6856. Fixes T10164.

- Make the profile image composer code use the underlying icon name instead of the top-level icon key, so it works instead of 404'ing.
- Change the button to show a preview of the profile icon instead of the text "Use Icon and Color".
- When creating a new non-milestone project, automatically set the profile image to the icon + color image.

Test Plan:
- Created several new projects, saw appropriate…