GeoIP policies fail on missing City data and RFC1918 client IPs

## What

policy looks up a missing/wrong context object (“client IP address not found in City database”). #20998 says it possibly fixes #12214.

## Want

- Policy looks up a missing/wrong context object (“client IP address not found in City database”)
- #20998 says it possibly fixes #12214

## Ideas this came from

- [#12214 Locked because of GeoIP Policy](https://github.com/goauthentik/authentik/issues/12214) — I added a GeoIP policy to the default authentication flow. I choose France as country. Now I cannot login anymore as I get the error "GeoIP: client IP address n
- [#20998 GeoIP policy module references wrong object in context](https://github.com/goauthentik/authentik/issues/20998) — Super simple GeoIP module with selected single country ALWAYS fails. GeoIP module references 2 different objects in context here it relies on "geoip" field in c

Start with the GeoIP policy and its context lookup, then read linked issues #20998 and #12214 to understand the reported failure. Reproduce the policy with missing City data and an RFC1918 client IP; done means both cases have the intended policy behavior instead of the reported lookup error.

Written by the indexing model from the issue text.