SUW: Don't export our WizardManager

Even though we disable this class when GMS is present, the
 intent-filters are still active and cause an activity resolver
 to be presented to the user. Disable export of this activity to
 work around this.

Change-Id: I5888c71b5fdb95e59e15366b66f56e7968e51f1a

AndroidManifest.xml

@@ -68,7 +68,7 @@
         <activity android:theme="@style/NoDisplay"
                   android:label="@string/activity_label_empty"
                   android:name=".wizardmanager.WizardManager"
-                  android:exported="true"
+                  android:exported="false"
                   android:excludeFromRecents="true"
                   android:configChanges="keyboard|keyboardHidden|mcc|mnc|orientation|screenSize"
                   android:immersive="true">