Add return animation functionality to TransitionAnimator.

Bug: 323863002
Flag: ACONFIG com.android.systemui.shared.return_animation_framework_library DISABLED
Test: Manually tested existing use cases with the flag on and off (same
behavior), added unit test

Change-Id: I391c6ae784871e17262649d0f17343ac87b6a6d4
diff --git a/packages/SystemUI/Android.bp b/packages/SystemUI/Android.bp
index f911269..5d1e2c3 100644
--- a/packages/SystemUI/Android.bp
+++ b/packages/SystemUI/Android.bp
@@ -233,6 +233,9 @@
     resource_dirs: [
         "tests/res",
     ],
+    asset_dirs: [
+        "tests/goldens",
+    ],
     static_libs: [
         "SystemUI-res",
         "WifiTrackerLib",
@@ -334,6 +337,8 @@
         "androidx.test.ext.junit",
         "androidx.test.ext.truth",
         "kotlin-test",
+        "platform-screenshot-diff-core",
+        "PlatformMotionTesting",
         "SystemUICustomizationTestUtils",
         "androidx.compose.runtime_runtime",
     ],