[CST-2710] avoid using empty user value as valid user

Author: Andrea Barbasso

src/app/accessibility/accessibility-settings.service.spec.ts

@@ -286,6 +286,7 @@ describe('accessibilitySettingsService', () => {
 
     it('should store settings in metadata when the user is authenticated', fakeAsync(() => {
       const user = new EPerson();
+      user._links = { self: { href: 'https://rest.api/eperson/123' }, groups: { href: 'https://rest.api/eperson/123/groups' } };
       authService.getAuthenticatedUserFromStoreIfAuthenticated = jasmine.createSpy().and.returnValue(of(user));
 
       service.setSettingsInAuthenticatedUserMetadata({}).subscribe();

src/app/accessibility/accessibility-settings.service.ts

@@ -204,7 +204,7 @@ export class AccessibilitySettingsService {
     return this.authService.getAuthenticatedUserFromStoreIfAuthenticated().pipe(
       take(1),
       switchMap(user => {
-        if (hasValue(user)) {
+        if (hasValue(user) && hasValue(user._links?.self)) {
           // EPerson has to be cloned, otherwise the EPerson's metadata can't be modified
           const clonedUser = cloneDeep(user);
           return this.setSettingsInMetadata(clonedUser, settings);