Remove test TFMs from PackageTesting

Follow-up on dotnet/runtime#90880

These listed TFMs are dotnet/runtime specific and shouldn't be hardcoded in arcade as they change every year.

Remove them form the props file and add them back directly in testPackages.proj in dotnet/runtime.

src/Microsoft.DotNet.PackageTesting/build/Microsoft.DotNet.PackageTesting.props

@@ -8,24 +8,6 @@
 
   <UsingTask TaskName="GetCompatiblePackageTargetFrameworks" AssemblyFile="$(DotNetPackageTestingAssembly)" />
   <UsingTask TaskName="VerifyClosure" AssemblyFile="$(DotNetPackageTestingAssembly)" />
-  <UsingTask TaskName="VerifyTypes" AssemblyFile="$(DotNetPackageTestingAssembly)"/>
-
-  <ItemGroup>
-    <SupportedTestFramework Include="net6.0" />
-    <SupportedTestFramework Include="net7.0" />
-    <SupportedTestFramework Include="net8.0" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <SupportedTestFramework Include="netstandard2.0" />
-    <SupportedTestFramework Include="netstandard2.1" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <SupportedTestFramework Include="net462" />
-    <SupportedTestFramework Include="net471" />
-    <SupportedTestFramework Include="net472" />
-    <SupportedTestFramework Include="net48" />
-  </ItemGroup>
+  <UsingTask TaskName="VerifyTypes" AssemblyFile="$(DotNetPackageTestingAssembly)" />
 
 </Project>