Gate WPF scenarios to internal runs due to CloseFailed on CI VMs

WPF Template and WPF SFC fail with CloseFailed on generic Helix CI
VMs because CloseMainWindow() doesn't work in headless environments.
This is the same issue that caused WinForms scenarios to be gated.
Gate both WPF scenarios behind SYSTEM_TEAMPROJECT=internal, with
IncludeVMFlakyScenarios override.

Author: LoopedBard3

eng/performance/scenarios.proj

@@ -43,11 +43,15 @@
       <ScenarioDirectoryName>windowsformslarge</ScenarioDirectoryName>
       <PayloadDirectory>$(ScenariosDir)%(ScenarioDirectoryName)</PayloadDirectory>
     </UIScenario>
-    <UIScenario Include="WPF Template" Condition="'$(TargetsWindows)' == 'true' AND '$(OS)' == 'Windows_NT'">
+    <!-- WPF Template: limited to internal runs due to CloseFailed on generic CI VMs (same issue as WinForms).
+      Override with /p:IncludeVMFlakyScenarios=true to include on other builds. -->
+    <UIScenario Include="WPF Template" Condition="'$(TargetsWindows)' == 'true' AND '$(OS)' == 'Windows_NT' AND ( '$(SYSTEM_TEAMPROJECT)' == 'internal' OR '$(IncludeVMFlakyScenarios)' == 'true' )">
       <ScenarioDirectoryName>wpf</ScenarioDirectoryName>
       <PayloadDirectory>$(ScenariosDir)%(ScenarioDirectoryName)</PayloadDirectory>
     </UIScenario>
-    <UIScenario Include="WPF SFC" Condition="'$(TargetsWindows)' == 'true' AND '$(OS)' == 'Windows_NT'">
+    <!-- WPF SFC: gated for consistency with WPF Template.
+      Override with /p:IncludeVMFlakyScenarios=true to include on other builds. -->
+    <UIScenario Include="WPF SFC" Condition="'$(TargetsWindows)' == 'true' AND '$(OS)' == 'Windows_NT' AND ( '$(SYSTEM_TEAMPROJECT)' == 'internal' OR '$(IncludeVMFlakyScenarios)' == 'true' )">
       <ScenarioDirectoryName>wpfsfc</ScenarioDirectoryName>
       <PayloadDirectory>$(ScenariosDir)%(ScenarioDirectoryName)</PayloadDirectory>
     </UIScenario>