TagsComponent: improve token refresh and error catching

[MonkeyDo]

@mayhem recently reported and helped me debug an issue he's been seeing that is breaking the Listening Now page.
It is to do with tags fetching and how I handled refreshing the MB token and retrying.

This PR improves a couple of things:

1. Wrap the tags fetch+retry in a try…catch block, that should prevent the broken page we were seeing
2. Return the token from the freshMBToken method so we can use it in the retry function; it seemed like the new token from the global context was not being used, not sure why
3. Show an error to the user if we can't get their tags for some reason. Some feedback is nice.

[mayhem]

Thank you for fixing it!