Add default picture and factorization of title in publication edition.

frontend/src/app/components/publication-edition/publication-edition.component.html

@@ -1,6 +1,6 @@
 <form [formGroup]="publicationEditionForm" (submit)="save()" ngNativeValidate>
     <header>
-        <h1>Modification de l'article {{ publication.title }}</h1>
+        <h1>{{title}}</h1>
     </header>
 
     <mat-tab-group dynamicHeight (selectedIndexChange)="onTabChange($event)">
@@ -19,7 +19,12 @@
                     </div>
 
                     <div class="picture-container">
-                        <img src="/api/pictures/{{publication.illustrationId}}" (click)="displayPictureSectionDialog()" matTooltip="Click to change illustration"/>
+                        @if (publication.illustrationId.length) {
+                            <img src="/api/pictures/{{publication.illustrationId}}" (click)="displayPictureSectionDialog()" matTooltip="Click to change illustration"/>
+                        } @else {
+                            <img src="/assets/images/default-picture.png" (click)="displayPictureSectionDialog()" matTooltip="Click to change illustration"/>
+                        }
+                        
                     </div>
                 </div>