Only run test project on .NET 9

.github/workflows/build-core-lib.yml

@@ -126,7 +126,7 @@ jobs:
      - name: Report Generator
        uses: danielpalme/ReportGenerator-GitHub-Action@5.2.4
        with:
-         reports: '**/coverage.net8.0.cobertura.xml;**/coverage.net9.0.cobertura.xml'
+         reports: '**/coverage.cobertura.xml;**/coverage.net8.0.cobertura.xml;**/coverage.net9.0.cobertura.xml'
          targetdir: 'CoverageReports'
          title: 'Unit Tests Code Coverage'
          classfilters: '-Microsoft.FluentUI.AspNetCore.Components.DesignTokens.*'

tests/Core/Microsoft.FluentUI.AspNetCore.Components.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Razor">
 
   <PropertyGroup>
-    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
+    <TargetFrameworks>net9.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <LangVersion>latest</LangVersion>