CtsTransitionTestCases: add parent style to the app theme

The issue b/139458376#comment9 indicates the missing value
(android:attr/windowTitleSize) in theme causes the error on activity
initialization. And this might be a cause of the flakiness.

This CL adds a parent style to the app style theme so that the app style
theme contains the missing value correctly.

Bug: 139458376
Test: Ran CtsTransitionTestCases locally and passed
Test: Forest passes (Run ID: L67000000358627313)
Change-Id: Ie4f0fa00013c2f23c3526a2aa0585687f69773eb
diff --git a/tests/tests/transition/res/values/styles.xml b/tests/tests/transition/res/values/styles.xml
index 00303c9..be2272e 100644
--- a/tests/tests/transition/res/values/styles.xml
+++ b/tests/tests/transition/res/values/styles.xml
@@ -14,7 +14,7 @@
      limitations under the License.
      -->
 <resources xmlns:android="http://schemas.android.com/apk/res/android">
-  <style name="Theme_NoSwipeDismiss">
+  <style name="Theme_NoSwipeDismiss" parent="android:Theme.DeviceDefault">
     <item name="android:windowSwipeToDismiss">false</item>
   </style>
 </resources>