Do not translate the AddDesktopButton on dismissing a TaskView

Flag: com.android.window.flags.enable_multiple_desktops_frontend
Flag: com.android.window.flags.enable_multiple_desktops_backend
Bug: 391872496
Test: m
Change-Id: I5b91ea1c419958b766db7da2f553f355a3817d2d
diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index 424271a..7a724d7 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -4346,6 +4346,11 @@
             PendingAnimation pendingAnimation,
             SplitAnimationTimings splitTimings,
             int index) {
+        // No need to translate the AddDesktopButton on dismissing a TaskView, which should be
+        // always at the right most position, even when dismissing the last TaskView.
+        if (view instanceof AddDesktopButton) {
+            return;
+        }
         FloatProperty translationProperty = view instanceof TaskView
                 ? ((TaskView) view).getPrimaryDismissTranslationProperty()
                 : getPagedOrientationHandler().getPrimaryViewTranslate();