Add "open group" step to copilot variant tests; revert for flaky adaptive card test (#5772)

* Initial plan

* Add opening group action to copilot test files before first snapshot

Co-authored-by: OEvgeny <2841858+OEvgeny@users.noreply.github.com>

* Revert opening group action from custom.skip.html (flaky test)

Co-authored-by: OEvgeny <2841858+OEvgeny@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: OEvgeny <2841858+OEvgeny@users.noreply.github.com>

Author: Copilot

__tests__/html2/part-grouping/folded.skip.html

@@ -286,10 +286,14 @@
       // 2nd is sent with status not set to show the work is in
       directLine.emulateIncomingActivity(withCreativeWorkStatus(activities.at(1), undefined));
 
+      await pageConditions.numActivitiesShown(3);
+
+      // When (copilot): opening the group
+      await host.click(document.querySelector('.collapsible-grouping__toggle'));
+
       // Then: show both activities in the list:
       // 1st with the loading indicator
       // 2nd with an empty status indicator
-      await pageConditions.numActivitiesShown(3);
       await host.snapshot('local');
 
       // When folding the list:

__tests__/html2/part-grouping/index.html

@@ -347,6 +347,12 @@
       // 1st with the loading indicator
       // 2nd with an empty status indicator
       await pageConditions.numActivitiesShown(3);
+
+      // When (copilot): opening the group
+      if (variant === 'copilot') {
+        await host.click(document.querySelector('.collapsible-grouping__toggle'));
+      }
+
       await host.snapshot('local');
 
       // When marking the 1st activity as 'Published':