feat: unhide --oidc-redirect-url server option (#28072)

Unhides the `--oidc-redirect-url` / `CODER_OIDC_REDIRECT_URL` server
option so it appears in `coder server --help` and the deployment
configuration docs.

- Removed `Hidden: true` from the option in `codersdk/deployment.go`
- Regenerated CLI golden files and docs via `make gen`

---

> Generated with Coder Agents on behalf of @Emyrk

cli/testdata/coder_server_--help.golden

@@ -807,6 +807,12 @@ OIDC OPTIONS:
       --oidc-name-field string, $CODER_OIDC_NAME_FIELD (default: name)
           OIDC claim field to use as the name.
 
+      --oidc-redirect-url url, $CODER_OIDC_REDIRECT_URL
+          Optional override of the default redirect url which uses the
+          deployment's access url. Useful in situations where a deployment has
+          more than 1 domain. Using this setting can also break OIDC, so use
+          with caution.
+
       --oidc-group-regex-filter regexp, $CODER_OIDC_GROUP_REGEX_FILTER (default: .*)
           If provided any group name not matching the regex is ignored. This
           allows for filtering out groups that are not needed. This filter is