feat: use discount info endpoint for streak discount information (#1763)

* feat: use discount info endpoint for streak discount information

* feat: pass course run key to discount code info call

* feat: move changes behind a flag

* fix: use async IIFE inside useEffect

* fix: fix line length

* fix: remove default value in dev

* fix: improve coverage by adding conditional test based on env value

* refactor: move logic inside function

* refactor: move functions to utils

* fix: ignore merge config