[wasm] Fix blazor/aot builds (#54653)

Backport of #54651 to release/6.0-preview6

`dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\6.0.0-preview.7.21321.15\Sdk\WasmApp.Native.targets(342,5): error : Could not find AOT cross compiler at $(_MonoAotCrossCompilerPath)=`

Make sure this is set for the aot path.

Co-authored-by: Ankit Jain <[email protected]>

Author: github-actions[bot]

src/mono/wasm/build/WasmApp.Native.targets

@@ -336,6 +336,10 @@ EMSCRIPTEN_KEEPALIVE void mono_wasm_load_profiler_aot (const char *desc) { mono_
   -->
 
   <Target Name="_WasmAotCompileApp" Condition="'$(RunAOTCompilation)' == 'true'">
+    <PropertyGroup>
+      <_MonoAotCrossCompilerPath>@(MonoAotCrossCompiler->WithMetadataValue('RuntimeIdentifier','browser-wasm'))</_MonoAotCrossCompilerPath>
+    </PropertyGroup>
+
     <Error Condition="'@(_WasmAssembliesInternal)' == ''" Text="Item _WasmAssembliesInternal is empty" />
     <Error Condition="'$(_IsEMSDKMissing)' == 'true'"
            Text="$(_EMSDKMissingErrorMessage) Emscripten SDK is required for AOT'ing assemblies." />