Remove fake bearer token from mutations.js

[timdrysdale]

There is a fake bearer token in the mutations.js which triggers an alert when pushing new commits to the repo. From memory, this was due to an error attempting to parse an empty string. It would be better to avoid the appearance of having secrets in the code-base, so that if any are accidentally included by a developer in future, it is less likely to be overlooked. (It's hard to manually parse the minified js that is dumped to screen when you commit a secret, which occurs when you have a secret scanner in your git hooks, leave a secret in the code, and push the distributed code to a repo that maintains current contents of servers).

[timdrysdale]

no longer relevant to the new code with xstate and the new API