Rework search page to use signals.

frontend/src/app/pages/search-publications/search-publications.service.ts

@@ -4,7 +4,6 @@ import { BehaviorSubject, Observable } from "rxjs";
 import { Publication } from "../../core/rest-services/publications/model/publication";
 import { MatSnackBar } from "@angular/material/snack-bar";
 
-
 @Injectable()
 export class SearchPublicationsService {
     private publicationRestService = inject(PublicationRestService);
@@ -16,7 +15,7 @@ export class SearchPublicationsService {
     get publications$(): Observable<Publication[]> {
         return this.publicationsSubject.asObservable();
     }
-    
+
     get isLoading$(): Observable<boolean> {
         return this.isLoadingSubject.asObservable();
     }
@@ -46,4 +45,4 @@ export class SearchPublicationsService {
                 this.isLoadedSubject.next(true);
             });
     }
-}
+}