www/caddy: Cleanup dialogs of old links, CDATA, check for typos

[Bishop-trevorstuart]

In the os-caddy plugin under General Settings/Auth Provider when you select Full help it gives you a blurb to aid with Forward Auth Provider. The URL provided beside "More Information" regarding Authentik is a dead URL.
URL given - https://docs.goauthentik.io/docs/providers/proxy/server_caddy

NOT confirmed but I THINK the detail is actually(maybe)
https://docs.goauthentik.io/add-secure-apps/providers/proxy/server_caddy/

OPNsense 25.7.9 (amd64).
os-caddy 2.0.4_2

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[Monviech]

I think since linkrot cannot be stopped, we should clean some of these links up in the helptexts.