Do not apply safe region letterboxing to test activity

- Since the TestActivity may no longer be full screen if safe region bounds are applied, the expected display hash will not be the expected one.
- The display hash received when a safe region letterbox is applied is non null but not the expected value.
- The safe region behavior can be verified in other tests in the class.

Bug: 404915525
Test: atest CtsWindowManagerDeviceDisplay
Flag: EXEMPT (bug fix)
Change-Id: I1dd058b6e474f720d4518ab993f9124dfb498eb0
diff --git a/tests/framework/base/windowmanager/AndroidManifest.xml b/tests/framework/base/windowmanager/AndroidManifest.xml
index dd74b12..4ac3056 100644
--- a/tests/framework/base/windowmanager/AndroidManifest.xml
+++ b/tests/framework/base/windowmanager/AndroidManifest.xml
@@ -490,7 +490,11 @@
                   android:screenOrientation="locked" />
 
         <activity android:name="android.server.wm.display.DisplayHashManagerTest$TestActivity"
-                   android:exported="true"/>
+                   android:exported="true">
+            <property
+                android:name="android.window.PROPERTY_COMPAT_ALLOW_SAFE_REGION_LETTERBOXING"
+                android:value="false" />
+        </activity>
 
         <activity android:name="android.server.wm.HelperActivities$ResizeableLeftActivity"
                   android:resizeableActivity="true"