Only update the task description when the task/description changes

- Instead of updating again for every task when we fetch recents, only update
  when the activities change

Bug: 69166452
Test: android.app.cts.TaskDescriptionTest
Change-Id: Idb66ee4c3ca6f637b6ab52c6d52dd1a09926c48f
diff --git a/services/core/java/com/android/server/am/TaskRecord.java b/services/core/java/com/android/server/am/TaskRecord.java
index 949f51f..290bebf 100644
--- a/services/core/java/com/android/server/am/TaskRecord.java
+++ b/services/core/java/com/android/server/am/TaskRecord.java
@@ -1616,6 +1616,9 @@
         final int effectiveRootIndex = findEffectiveRootIndex();
         final ActivityRecord r = mActivities.get(effectiveRootIndex);
         setIntent(r);
+
+        // Update the task description when the activities change
+        updateTaskDescription();
     }
 
     void saveToXml(XmlSerializer out) throws IOException, XmlPullParserException {