The icon list isn't cached in Icon Quick Action.

The Icon Quick Action doesn't cache the icon list.

Setps to reproduce:

1. Edit a page
2. Open the network tab of the Dev Tools
3. Open the Icon Quick Action by typing "/icon" and pressing enter.
4. Type "wiki"

Expected Result: Only one request is made when opening the icon Quick Action.
Current Result: A request is made with every key press.