Auth magic.link cached token should be purged after logout

[LBrian]

[Context]
authentication, magic.link

[Root cause]
I believe this a side effect from #2555 to cache token for 10 mins.

[Reproduce]
Log in user A and log out then log in user B right after, getCurrentUser returns user A metadata instead since user A's token is cached, reload the page fix this issue.

[Solution]
Purge cached token in logout function

logout: async () => {
  token = null
  expireTime = 0
  await client.user.logout()
},