Add issue reference to SpecializedTestRunsheetBuilderBase.targets comment (#11749)

* Initial plan

* Update comment in SpecializedTestRunsheetBuilderBase.targets to reference issue #11747

Co-authored-by: radical <1472+radical@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: radical <1472+radical@users.noreply.github.com>

Author: Copilot

eng/SpecializedTestRunsheetBuilderBase.targets

@@ -35,6 +35,7 @@
 
   <!--
     Skip Templates, Playground, and EndToEnd tests for specialized test workflows as these are known to be broken.
+    See https://github.com/dotnet/aspire/issues/11747 for tracking the work to enable these tests.
     -->
   <PropertyGroup>
     <_IsUnsupportedProject>false</_IsUnsupportedProject>