Changed CtsWindowManagerHostTestCases to not use DeviceDefault.

Modifying the value of the attribute windowDrawsSystemBarBackgrounds in
the DeviceDefault themes caused some CtsWindowManagerHostTestCases to
fail. Updating these to run with the Material theme instead removes the
issue.

Bug: 63559762
Change-Id: I6610c43312a195dd6447bbf49e060339e610fcb2
diff --git a/hostsidetests/services/activityandwindowmanager/windowmanager/frametestapp/AndroidManifest.xml b/hostsidetests/services/activityandwindowmanager/windowmanager/frametestapp/AndroidManifest.xml
index 46c9b03..7f899c2 100755
--- a/hostsidetests/services/activityandwindowmanager/windowmanager/frametestapp/AndroidManifest.xml
+++ b/hostsidetests/services/activityandwindowmanager/windowmanager/frametestapp/AndroidManifest.xml
@@ -18,7 +18,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           xmlns:androidprv="http://schemas.android.com/apk/prv/res/android"
           package="android.server.FrameTestApp">
-    <application>
+    <application android:theme="@android:style/Theme.Material">
         <activity android:name=".DialogTestActivity"
                 android:exported="true"
         />