InProcess coverlet data collector isn't running when enabling coverlet from the runsettings file

[ViktorHofer]

If the coverlet data collector is configured via a .runsettings file and set to enabled=True, the InProcessDataCollector isn't added to the vstest.console's internal .runsettings memory representation. The impact is that the code coverage measurement runs as expected but the results aren't stable because of the missing in-proc collector: https://github.com/coverlet-coverage/coverlet/issues/834.

Example runsettings file in which coverlet data collector is enabled:

<?xml version="1.0" encoding="utf-8"?>
<RunSettings>
  <DataCollectionRunSettings>
    <DataCollectors>
      <DataCollector friendlyName="XPlat code coverage" enabled="True">
        <Configuration>
          <Include>[System.Text.RegularExpressions]*</Include>
          <ExcludeByFile>C:\git\runtime3\src\libraries\Common\src\System\SR.*,C:\git\runtime3\src\libraries\Common\src\System\NotImplemented.cs</ExcludeByFile>
          <IncludeDirectory>C:\git\runtime3\artifacts\bin\testhost\net5.0-Windows_NT-Debug-x64\shared\Microsoft.NETCore.App\5.0.0</IncludeDirectory>
          <Format>opencover</Format>
          <SingleHit>false</SingleHit>
          <UseSourceLink>true</UseSourceLink>
          <IncludeTestAssembly>false</IncludeTestAssembly>
        </Configuration>
      </DataCollector>
    </DataCollectors>
  </DataCollectionRunSettings>
</RunSettings>

I have a fix for that locally and will submit a PR.

cc @MarcoRossignoli

[Evangelink]

@MarcoRossignoli Could you please investigate this when you have some time?