refactor: 增加 ClassString 样式

Author: ArgoZhang

src/components/BootstrapBlazor.SummerNote/Components/Editor/Editor.razor

@@ -7,6 +7,6 @@
 {
     <BootstrapLabel required="@Required" for="@Id" ShowLabelTooltip="ShowLabelTooltip" Value="@DisplayText" />
 }
-<div @attributes="@AdditionalAttributes" id="@Id" class="editor" data-bb-submit="@ShowSubmitString">
+<div @attributes="@AdditionalAttributes" id="@Id" class="@ClassString" data-bb-submit="@ShowSubmitString">
     <div class="@EditClassString" placeholder="@PlaceHolder"></div>
 </div>

src/components/BootstrapBlazor.SummerNote/Components/Editor/Editor.razor.cs

@@ -13,6 +13,10 @@ namespace BootstrapBlazor.Components;
 /// </summary>
 public partial class Editor
 {
+    private string? ClassString => CssBuilder.Default("editor")
+        .AddClass(CssClass).AddClass(ValidCss)
+        .Build();
+
     /// <summary>
     /// 获得 Editor 样式
     /// </summary>