fix(Drawer): missing position variable (dotnetcore#6906)

* refactor: 增加判断条件

* chore: bump version 9.11.2

Author: ArgoZhang

src/BootstrapBlazor/BootstrapBlazor.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Razor">
 
   <PropertyGroup>
-    <Version>9.11.2-beta07</Version>
+    <Version>9.11.2</Version>
   </PropertyGroup>
 
   <ItemGroup>

src/BootstrapBlazor/Components/Drawer/Drawer.razor.cs

@@ -19,7 +19,7 @@ public partial class Drawer
         .Build();
 
     private string? StyleString => CssBuilder.Default()
-        .AddClass($"--bb-drawer-position: {Position};")
+        .AddClass($"--bb-drawer-position: {Position};", !string.IsNullOrEmpty(Position))
         .AddClass($"--bb-drawer-zindex: {ZIndex};", ZIndex.HasValue)
         .AddStyleFromAttributes(AdditionalAttributes)
         .Build();