Convert observables to signals.

frontend/src/app/pages/home/home.component.html

@@ -1,10 +1,10 @@
 <h1 i18n>Last publications</h1>
-@if ((isLoading$ | async) === true) {
+@if ((isLoading())) {
     <h2 i18n>Publications loading...</h2>
     <mat-spinner></mat-spinner>
 } @else {
-    @if ((publications$ | async) != []) {
-        <app-publication-list [publications$]="publications$"></app-publication-list>
+    @if (publications(); as publications) {
+        <app-publication-list [publications]="publications"></app-publication-list>
     } @else {
         <h2 i18n>No any publication.</h2>
     }