chore: 更新配置开发模式使用单框架

Author: ArgoZhang

src/BootstrapBlazor/Directory.Build.props

@@ -16,7 +16,11 @@
     <IsPackable>true</IsPackable>
   </PropertyGroup>
 
-  <PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)' == 'Debug'">
+    <TargetFramework>net9.0</TargetFramework>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)' != 'Debug'">
     <TargetFrameworks>net6.0;net7.0;net8.0;net9.0</TargetFrameworks>
   </PropertyGroup>