Skip to set the background color of TDA during Animation with a transparent color.

- Some launcher doesn't want to set the background color of TDA during Animation, since it can hide the other apps.

Bug: 222153339
Test: Check if the other apps are showing during the transition.
Change-Id: I5658e0b416b0c8200714fce2fe7b30ce084d921b

services/core/java/com/android/server/wm/WindowContainer.java

@@ -70,6 +70,7 @@ import android.annotation.Nullable;
 import android.content.Context;
 import android.content.pm.ActivityInfo;
 import android.content.res.Configuration;
+import android.graphics.Color;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.os.Debug;
@@ -3563,7 +3564,7 @@ class WindowContainer<E extends WindowContainer> extends ConfigurationContainer<
         private void setTaskBackgroundColor(@ColorInt int backgroundColor) {
             TaskDisplayArea taskDisplayArea = getTaskDisplayArea();
 
-            if (taskDisplayArea != null) {
+            if (taskDisplayArea != null && backgroundColor != Color.TRANSPARENT) {
                 taskDisplayArea.setBackgroundColor(backgroundColor);
 
                 // Atomic counter to make sure the clearColor callback is only called one.