Migrate GeneratedPreviewTest to multivalent

Test: atest NexusLauncherRoboTests
Test: SysUI studio
Fix: 325088369
Flag: TEST_ONLY
Change-Id: I2c88a357c8ac5fb0171a70e850be25e8fb11de33
diff --git a/tests/Android.bp b/tests/Android.bp
index 1dcb2a6..e51242f 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -211,6 +211,7 @@
         "Launcher3TestResources",
         "SystemUISharedLib",
         "launcher-testing-shared",
+        "android.appwidget.flags-aconfig-java",
     ],
     libs: [
         "android.test.runner",