Cascading logout page not implemented

Hi,

**Context**

We just implemented this plugin theme in a Keycloak POC with 2 Drupal frontend application.
Those applications are connected to Keycloak using the "drupal/oidc" module (https://www.drupal.org/project/oidc).

**Experimented**

When we are connected to both applications, then the logout link will redirect to Keycloak logout page which triggers each front logout process.
In that case, the logout screen is quickly displayed using native Keycloak theme (with grey background colors).

**Expected**

The logout page should be display with the respect of DSFR theme.

Many thanks