TF-4370 Fix selector/key wiring: modal instantiation does not pass the key the test expects

lib/features/labels/presentation/label_controller.dart

@@ -148,6 +148,7 @@ class LabelController extends BaseController with LabelContextMenuMixin {
 
     await DialogRouter().openDialogModal(
       child: CreateNewLabelModal(
+        key: const Key('create_new_label_modal'),
         labels: labels,
         onLabelActionCallback: (label) => _createNewLabel(accountId, label),
       ),

lib/features/labels/presentation/widgets/create_new_label_modal.dart

@@ -363,6 +363,7 @@ class _CreateNewLabelModalState extends State<CreateNewLabelModal> {
 
   void _clearInputFocus() {
     _nameInputFocusNode.unfocus();
+    _descriptionInputFocusNode.unfocus();
   }
 
   void _onCreateNewLabel() {
@@ -373,7 +374,9 @@ class _CreateNewLabelModalState extends State<CreateNewLabelModal> {
       color: _selectedColor != null
           ? HexColor(_selectedColor!.toHexTriplet())
           : null,
-      description: _descriptionInputController.text,
+      description: _descriptionInputController.text.trim().isEmpty
+          ? null
+          : _descriptionInputController.text.trim(),
     );
     widget.onLabelActionCallback(newLabel);