Update dashboard UI version mismatch logic to redirect to a version-enabled URL to get past cached index.html

[MichaelBurgess]

When we get a mismatched UI and server version, we show a warning error. However we still find that people are unable to clear this unless they do full hard refreshes, or restart browsers.

We can detect this and append a version string to the URL and force a reload, meaning we'll round-trip to the server and get the correct assets.