Add a way to toggle inlay hints with modifiers #2 (#25766)

https://github.com/zed-industries/zed/pull/25752 with fixes on top

* Ensures no flickering happens for all modifiers `: false` case
* Dismisses the toggled state on focus out
* Reworks cache state so that "enabled" and "toggled by modifiers" are
different states with their own lifecycle

Release Notes:

- N/A