Fixes errors not announced on duration picker

Fixes AB#1065

desktop/src/@batch-flask/ui/duration-picker/duration-picker.html

@@ -16,16 +16,17 @@
         </bl-select>
     </div>
 </div>
-<div class="error" *ngIf="invalidTimeNumber">
+<div class="error-container" role="alert">
+    <div class="error" *ngIf="invalidTimeNumber">
         Input should be a valid positive number
-</div>
-<div class="error" *ngIf="required && !this.time">
+    </div>
+    <div class="error" *ngIf="required && !this.time">
         Input is required
-</div>
-<div class="error" *ngIf="invalidCustomDuration">
+    </div>
+    <div class="error" *ngIf="invalidCustomDuration">
         This is not a valid ISO 8601 duration <i>(e.g. PT1M, P1D)</i>
-</div>
-<div class="error" *ngIf="invalidDurationValue">
+    </div>
+    <div class="error" *ngIf="invalidDurationValue">
         Input must be less than 10675199 days
+    </div>
 </div>
-

desktop/src/@batch-flask/ui/duration-picker/duration-picker.scss

@@ -13,7 +13,7 @@ bl-duration-picker {
         }
     }
 
-    > .error {
+    > .error-container > .error {
         color: $danger-color;
     }
 }