Fix build when using source generators coming from NuGet packages. (#6793)

Fixes #6792

Author: ThomasGoulet73

src/Microsoft.DotNet.Wpf/src/PresentationBuildTasks/Microsoft.WinFX.targets

@@ -435,6 +435,11 @@
           <_IntermediateOutputPathNoTargetFrameworkOrRID>$([System.Text.RegularExpressions.Regex]::Replace($(_IntermediateOutputPathNoTargetFrameworkOrRID), "$(TargetFramework)\\$",, System.Text.RegularExpressions.RegexOptions.IgnoreCase))</_IntermediateOutputPathNoTargetFrameworkOrRID>
       </PropertyGroup>
 
+      <ItemGroup>
+          <!-- Include analyzers that are coming from a FrameworkReference in the temporary target assembly project. -->
+          <_TemporaryTargetAssemblyAnalyzer Include="@(Analyzer)" Condition="'%(Analyzer.FrameworkReferenceName)' != ''" />
+      </ItemGroup>
+
        <!--  Use the legacy .NET Framework/.NET Core 3.0 GenerateTemporaryTargetAssembly path if 'IncludePackageReferencesDuringMarkupCompilation' is 'false',. -->
        <GenerateTemporaryTargetAssembly
                 CurrentProject="$(MSBuildProjectFullPath)"
@@ -450,7 +455,7 @@
                 CompileTargetName="$(_CompileTargetNameForLocalType)"
                 GenerateTemporaryTargetAssemblyDebuggingInformation="$(GenerateTemporaryTargetAssemblyDebuggingInformation)"
                 IncludePackageReferencesDuringMarkupCompilation="$(IncludePackageReferencesDuringMarkupCompilation)"
-                Analyzers="@(Analyzer)"
+                Analyzers="@(_TemporaryTargetAssemblyAnalyzer)"
                 TemporaryTargetAssemblyProjectName="$(_TemporaryTargetAssemblyProjectName)"
                 MSBuildProjectExtensionsPath="$(MSBuildProjectExtensionsPath)"
                  >