fix: 修复 Value 设置 IsActive 状态逻辑

Author: ArgoZhang

src/BootstrapBlazor/Components/Select/SelectTree.razor.cs

@@ -232,6 +232,7 @@ private async Task TriggerItemChanged(Func<TreeViewItem<TValue>, bool> predicate
         var currentItem = GetExpandedItems().FirstOrDefault(predicate);
         if (currentItem != null)
         {
+            currentItem.IsActive = true;
             await ItemChanged(currentItem);
         }
     }