fix(authentication-client): Ensure reAuthenticate works in parallel with other requests

[daffl]

Running reAuthenticate in parallel with other requests that need authentication e.g. like this:

const [authresult, dummies] = await Promise.all([
  app.reAuthenticate(),
  app.service('dummy').find()
])

Did not work though it should work the same as with authenticate which ensures that all requests wait for the current authentication to complete.