Default JsonSerializerIsReflectionEnabledByDefault to true on Blazor WASM. (#31909)

Author: eerhardt

src/BlazorWasmSdk/Targets/Microsoft.NET.Sdk.BlazorWebAssembly.Current.targets

@@ -17,6 +17,9 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!-- Trimmer defaults that depend on user-definable settings.
         This must be configured before it's initialized in the .NET SDK targets (which are imported by the Razor SDK). -->
     <SuppressTrimAnalysisWarnings Condition="'$(SuppressTrimAnalysisWarnings)' == '' And '$(TrimmerDefaultAction)' != 'link'">true</SuppressTrimAnalysisWarnings>
+
+    <!-- Similarly these feature switches must be configured before they are initialized in imported SDKs -->
+    <JsonSerializerIsReflectionEnabledByDefault Condition="'$(JsonSerializerIsReflectionEnabledByDefault)' == ''">true</JsonSerializerIsReflectionEnabledByDefault>
   </PropertyGroup>
 
   <Import Sdk="Microsoft.NET.Sdk.Razor" Project="Sdk.targets" />