Bug 42705: Make http-client.js handle svc endpoint error

The afterEach calls cy.login() then immediately posts to the syspref endpoint. On CI, the machine is slow enough that the POST fires before the login
redirect completes — no valid session yet — so the endpoint returns a C4::Service auth error in this format:

{ "type": "auth", "message": "expired" }

http-client.js only knew how to parse modern REST API errors (json.error or json.errors[]). Neither field exists here, so json.errors.map(...) crashed with a TypeError instead of surfacing the actual error message.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

koha-tmpl/intranet-tmpl/prog/js/fetch/http-client.js

@@ -80,7 +80,8 @@ class HttpClient {
                             let json = JSON.parse(text);
                             message =
                                 json.error ||
-                                json.errors.map(e => e.message).join("\n") ||
+                                json.errors?.map(e => e.message).join("\n") ||
+                                json.message ||
                                 json;
                         } else {
                             message = response.statusText;