[main] Update dependencies from microsoft/testfx (#8697)

Co-authored-by: dotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>

Author: dotnet-maestro[bot]

eng/Version.Details.xml

@@ -17,13 +17,13 @@
       <Uri>https://dev.azure.com/devdiv/DevDiv/_git/vs-code-coverage</Uri>
       <Sha>1c843cff315268b8c61d2c1ee22103f393baba77</Sha>
     </Dependency>
-    <Dependency Name="MSTest" Version="4.3.0-preview.26278.8">
+    <Dependency Name="MSTest" Version="4.3.0-preview.26279.6">
       <Uri>https://github.com/microsoft/testfx</Uri>
-      <Sha>255425b320d94dbef82699450d106f64a1f49d42</Sha>
+      <Sha>36eba942f8f119a577e567c9e9d032603e38a5a6</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Testing.Platform" Version="2.3.0-preview.26278.8">
+    <Dependency Name="Microsoft.Testing.Platform" Version="2.3.0-preview.26279.6">
       <Uri>https://github.com/microsoft/testfx</Uri>
-      <Sha>255425b320d94dbef82699450d106f64a1f49d42</Sha>
+      <Sha>36eba942f8f119a577e567c9e9d032603e38a5a6</Sha>
     </Dependency>
   </ToolsetDependencies>
 </Dependencies>

eng/Versions.props

@@ -10,7 +10,7 @@
     <MicrosoftDotNetBuildTasksTemplatingPackageVersion>11.0.0-beta.26279.3</MicrosoftDotNetBuildTasksTemplatingPackageVersion>
     <MicrosoftTestingExtensionsCodeCoverageVersion>18.8.0-preview.26271.2</MicrosoftTestingExtensionsCodeCoverageVersion>
     <!-- empty line to avoid merge conflicts for darc PRs to update CC and MSTest+MTP -->
-    <MSTestVersion>4.3.0-preview.26278.8</MSTestVersion>
-    <MicrosoftTestingPlatformVersion>2.3.0-preview.26278.8</MicrosoftTestingPlatformVersion>
+    <MSTestVersion>4.3.0-preview.26279.6</MSTestVersion>
+    <MicrosoftTestingPlatformVersion>2.3.0-preview.26279.6</MicrosoftTestingPlatformVersion>
   </PropertyGroup>
 </Project>