Remove `troubleshoot/pages` from admin tool or fix them

[ioannakok]

There's a https://frontend.gutools.co.uk/troubleshoot/pages endpoint in the admin tool

Currently, when we click test, it is failing to get the loadbalancer url

Is this endpoint used? If not, we can remove all the relevant code, otherwise fix the error.

[ioannakok]

If CP are not using we can delete it