Fix token expired

[Aschen]

What does this PR do?

Since we use the error code it's better to rely on the error id instead of the message.
The error message when the token has expired has changed and so the corresponding event was not trigger anymore.

This PR fix this by using the error id instead.

How should this be manually tested?

const {
  Kuzzle,
  Http
} = require('./index')

const kuzzle = new Kuzzle(new Http('localhost'))

kuzzle.on('networkError', console.error);

kuzzle.on('tokenExpired', () => {
  console.log('Expired')
});
(async () => {
  await kuzzle.connect()

  await kuzzle.security.createUser('admin', {
    content: { profileIds: [ 'default' ] },
    credentials: { local: { username: 'admin', password: 'admin' } }
  });
  await kuzzle.auth.login('local', { username: 'admin', password: 'admin' }, '2s')

  setTimeout(async () => {
    try {
      await kuzzle.server.now()

    }
    catch (error) {
      console.log(error)
    }
  }, 3000)
})();

Other changes

• use tokenExpired event in Realtime and Auth controller instead of directly calling the methods from Kuzzle object

[codecov]

Codecov Report

Merging #512 into 7-dev will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##            7-dev     #512   +/-   ##
=======================================
  Coverage   95.81%   95.82%           
=======================================
  Files          32       32           
  Lines        1315     1316    +1     
=======================================
+ Hits         1260     1261    +1     
  Misses         55       55           

Impacted Files	Coverage Δ
src/Kuzzle.js	93.91% <ø> (-0.06%)	⬇️
src/controllers/Auth.js	93.75% <100.00%> (+0.20%)	⬆️
src/controllers/Realtime.js	97.82% <100.00%> (+0.04%)	⬆️
src/protocols/abstract/Base.js	94.00% <100.00%> (ø)

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