feat($http): pass response status code to data transform functions

Fixes #10324
Closes #6734

@caitp this is an alternative to #6734 discussed today. I'm still not sure what it the best: to pass status code or just success / error flag (like in #6734). The first approach is more flexible but people will have to duplicate the `isSuccess` "logic".
Since you are at it, that `{` seems out of place...