fix mapping template

src/app/mapping/mapping.component.html

@@ -102,10 +102,10 @@
                             <div class="col-3"><label for="{{data.key}}">{{dcatVocabulary[data.key].identifier}}</label>
                             </div>
                             <div class="col-7">
-                                <ng-container #normal>
+                                <ng-template #normal>
                                     <input nbInput [ngModel]="data.value"
                                         (ngModelChange)="mappedMetadatas[index].set(data.key, $event)" />
-                                </ng-container>
+                                </ng-template>
                                 <ng-container *ngIf="isArray(data.value) && !isMultiple(dcatVocabulary[data.key].identifier); else normal">
                                     <input nbInput [ngModel]="data.value[0]"
                                         (ngModelChange)="mappedMetadatas[index].set(data.key, $event)" />