Fix `REACT_APP_API_URL` config logic
Porting a few changes from !479 (merged), including a fix for the new REACT_APP_API_URL
config logic (the ternary has to be wrapped in parens).
Porting a few changes from !479 (merged), including a fix for the new REACT_APP_API_URL
config logic (the ternary has to be wrapped in parens).