[Bug] implement 'error' page for when users are not yet a Judge on keycloak

[Lordfirespeed]

What Happened?

the page that is meant to say 'forbidden' etc. says '404 not found', which is confusing

Steps to Reproduce

login using an account without judge/hacker permissions

What device(s) are you seeing this issue on?

No response

What browser are you seeing this issue on?

No response

Possible Solutions

No response

Additional Info

No response

[MatthewWiddop]

@Lordfirespeed, are you still able to replicate this bug? I remember seeing 403 Forbidden when setting up an account. Would it be better if the page had a more specific error message?

[Lordfirespeed]

The error page was added in 54a05b4 so this is out of date

Keeping this open: when a user is directed to the error page and they don't have the 'hacker' role, we should add some detail to the message like "if you believe you should have access, talk to an organiser"