Include IWindowContainer token along with StackInfo

This is needed for stacks to participate in transactions.
Most immediate use-case will be PiP during rotation

Bug: 119687367
Test: Added ActivityTaskManagerServiceTests#testStackTransaction

Change-Id: I50a5c3cea4f23f2be4e55ba38f8a5371fa9dfe79
diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index 3ef848c..79c76b9 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -3243,7 +3243,7 @@
 
     private void sanitizeAndApplyConfigChange(ConfigurationContainer container,
             WindowContainerTransaction.Change change) {
-        if (!(container instanceof Task)) {
+        if (!(container instanceof Task || container instanceof ActivityStack)) {
             throw new RuntimeException("Invalid token in task transaction");
         }
         // The "client"-facing API should prevent bad changes; however, just in case, sanitize