Fix Authelia OIDC client secret syntax to use template filter

expand-env double-processes substituted values so $ in bcrypt hashes
get re-expanded. Switch back to template filter with {{ env "VAR" }}
syntax which returns values as-is.

authelia/config/configuration.yaml

@@ -65,7 +65,7 @@ identity_providers:
     clients:
       - client_id: open-webui
         client_name: Open WebUI
-        client_secret: '${AUTHELIA_OIDC_CLIENT_SECRET_OPEN_WEBUI}'
+        client_secret: '{{ env "AUTHELIA_OIDC_CLIENT_SECRET_OPEN_WEBUI" }}'
         public: false
         authorization_policy: one_factor
         token_endpoint_auth_method: client_secret_post
@@ -79,7 +79,7 @@ identity_providers:
 
       - client_id: linkding
         client_name: Linkding
-        client_secret: '${AUTHELIA_OIDC_CLIENT_SECRET_LINKDING}'
+        client_secret: '{{ env "AUTHELIA_OIDC_CLIENT_SECRET_LINKDING" }}'
         public: false
         authorization_policy: one_factor
         token_endpoint_auth_method: client_secret_post