checkResetTokenValidity throws undefined

[oallouch]

Hi,
The errors thrown from checkResetTokenValidity are undefined or lack codes (see UserController.js line 78).
That makes error treatment quite difficult.

Olivier

[flovilmart]

If the error is undefined, it means that no link exists, if the error is 'The password reset link has expired'. Errors could be indeed improved. Do you wanna work on a PR for that?

[dplewis]

Closing via #5332