Error dialog component on dataset wizard (update)

* On single error case, show it indepentently (not as list item)

dmp-frontend/src/common/forms/form-validation-errors-dialog/form-validation-errors-dialog.component.html

@@ -5,9 +5,14 @@
 	</div>
 	<div class="row content">
 		<div class="col p-0">
-			<ul class="error-list">
+			<ng-container *ngIf="errorMessages">
+				<ul class="error-list" *ngIf="errorMessages.length > 1 else singleError">
 					<li *ngFor="let error of errorMessages">{{error}}</li>
 				</ul>
+			</ng-container>
+			<ng-template #singleError>
+				<span>{{errorMessages[0]}}</span>
+			</ng-template>
 		</div>
 	</div>
 	<div class="row">