[task] validate token and handle 401 redirect.

[leoGalani]

if the localstorage hash for some reason is in the wrong format, we need to check and clean it and redirect the user to the login page

code to be fixed: https://github.com/AgileTesters/sherlock_test_manager/blob/main/sherlock_frontend/src/main.js#L16-L23

for 401 redirects to the login page, use https://github.com/axios/axios#interceptors