WCF test targets should be revisited

[wfurt]

Looking at the SendToHelix.proj I see

  <ItemGroup Condition="'$(TestJob)' == 'Linux'" >
    <HelixTargetQueue Include="SLES.15.Amd64.Open" />
    <HelixTargetQueue Include="(Fedora.41.Amd64.Open)ubuntu.2204.amd64.open@mcr.microsoft.com/dotnet-buildtools/prereqs:fedora-41-helix" /> 
    <HelixTargetQueue Include="Ubuntu.2204.Amd64.Open" />
    <HelixTargetQueue Include="(Debian.12.Amd64.Open)Ubuntu.2204.Amd64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-12-helix-amd64" />
    <HelixTargetQueue Include="(Mariner.2.0.Amd64.Open)Ubuntu.2204.Amd64.open@mcr.microsoft.com/dotnet-buildtools/prereqs:cbl-mariner-2.0-helix-amd64" />
    <HelixTargetQueue Include="(openSUSE.15.6.Amd64.Open)Ubuntu.2204.Amd64.open@mcr.microsoft.com/dotnet-buildtools/prereqs:opensuse-15.6-helix-amd64" />
  </ItemGroup>

it seems like SLES and OpenSUSE are somewhat redundant - one with commercial support and one without.
I'm curious if we could drop the SLES.15. and depend only on containers. That would allow us to retire that queue and associated infrastructure maintenance.

On similar note, mariner-2.0 is out of support, replaced by AzureLinux.3
For reference, here is what .NET runtime tests on:
https://github.com/dotnet/runtime/blob/main/eng/pipelines/libraries/helix-queues-setup.yml

Im happy to put up PR @mconnew if you want me to

[mconnew]

That sounds good to me. Feel free to submit a PR. Our list was based on the runtime repo from a while ago.