Don't send jwt when doing the login action

[jenow]

What does this PR do?

Don't send the jwt when doing a login action. This prevent to be able to do a login after a tokenExpired happen without resetting the jwt (kuzzle.jwt = null)

[codecov-io]

Codecov Report

Merging #372 into 6-dev will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##            6-dev     #372   +/-   ##
=======================================
  Coverage   96.61%   96.61%           
=======================================
  Files          28       28           
  Lines        1417     1417           
=======================================
  Hits         1369     1369           
  Misses         48       48

Impacted Files	Coverage Δ
src/Kuzzle.js	95.41% <ø> (ø)	⬆️

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[scottinet]

While ignoring the JWT on a login action is not a bad idea, I think there is another problem with the use case you mention.

Namely, the JWT should be unset after a tokenExpired event has been received: https://github.com/kuzzleio/sdk-javascript/blob/6-beta/src/Kuzzle.js#L93

So, if you're right about your use case, then it means that there is a bug with that event.

[scottinet]

Ignore my previous comment: I'll fix that issue in another PR. After discussing the issue internally, not sending the JWT in login requests seems a reasonable thing to do.