early return if added

lib/core/viewModel/labs_view_model.dart

@@ -171,8 +171,12 @@ class LabsViewModel extends BaseViewModel {
   }
 
   Future<void> openPDF() async {
-    if(this.attachments?.isNotEmpty == true ){
-      if(this.attachments?.first.base64Content == null || this.attachments?.first.base64Content?.isEmpty == true){
+    if (this.attachments?.isEmpty == true) {
+      Utils.showErrorToast("Unable to show Attachments");
+      return;
+    }
+
+    if(this.attachments?.first.base64Content == null || this.attachments?.first.base64Content?.isEmpty == true){
         Utils.showErrorToast("Unable to show Attachments");
         return;
       }
@@ -183,6 +187,5 @@ class LabsViewModel extends BaseViewModel {
       } catch (ex) {
         Utils.showErrorToast("Unable to show Attachments");
       }
-    }
   }
 }