Describe the bug

Admin console impersonate feature does not properly work on cross-domain setup when hostname-admin does not match realm hostname.

Impersonate feature invokes admin endpoint on admin hostname which sets cookies in a response, but they are set for a wrong domain:

POST https://admin-host/admin/realms/example/users/99c1caa0-9f15-11ec-bfac-7446a03ae071/impersonation

```
set-cookie: KEYCLOAK_IDENTITY=snip; Version=1; Path=/realms/example/; SameSite=None; Secure; HttpOnly
set-cookie: KEYCLOAK_SESSION=example/99c1caa0-9f15-11ec-bfac-7446a03ae071/snip; Version=1; Expires=Wed, 09-Mar-2022 04:33:24 GMT; Max-Age=36000; Path=/realms/example/; SameSite=None; Secure
```
It then opens account endpoint on admin hostname which redirects to hostname for the realm, where session is not present since cookies are not set for that domain.

Version

17.0.0

Expected behavior

Impersonation flow is aware of different admin hostname and performs redirects to end up starting session on realm hostname

Actual behavior

Impersonation flow starts session on admin hostname which is then unusable.

How to Reproduce?

Setup keycloak with separate domains for hostname and hostname-admin. Attempt to use impersonation.

Anything else?

This is not a new issue https://keycloak.discourse.group/t/cross-domain-impersonate/10302