fix: correct language.slovak native name in sk.json5 and add setLanguage('sk') test

Agent-Logs-Url: https://github.com/dataquest-dev/dspace-angular/sessions/2c99c167-9def-4bea-8e3d-65b580ba03ac

Co-authored-by: Kasinhou <129340513+Kasinhou@users.noreply.github.com>

Author: Copilot

src/app/clarin-navbar-top/clarin-navbar-top.component.spec.ts

@@ -65,6 +65,13 @@ describe('ClarinNavbarTopComponent', () => {
       });
   });
 
+  it('should set Slovak language when sk flag is clicked', () => {
+    const localeService = TestBed.inject(LocaleService);
+    component.setLanguage('sk');
+    expect(localeService.setCurrentLanguageCode).toHaveBeenCalledWith('sk');
+    expect(localeService.refreshAfterChangeLanguage).toHaveBeenCalled();
+  });
+
   function getMockLocaleService(): LocaleService {
     return jasmine.createSpyObj('LocaleService', {
       setCurrentLanguageCode: jasmine.createSpy('setCurrentLanguageCode'),

src/assets/i18n/sk.json5

@@ -9661,7 +9661,7 @@
   "language.czech": "Čeština",
 
   // "language.slovak": "Slovak",
-  "language.slovak": "Slovenština",
+  "language.slovak": "Slovenčina",
 
   // "repository.policy.page": "Change me: policy page",
   "repository.policy.page": "policy page",