opengl: tests: Add explict android:exported flag to manifests on GLDual.apk

After Android S+, it's required to add android:exported flag on manifests
if an intent filter is defined. We have added this flag on serveral apps
by previous change[1]. This is a follow-up change for GLDual.apk.

[1]: https://android.googlesource.com/platform/frameworks/native/+/8e8ae4222f9fb0499af755a4255cceb89a79bd78

Test: The GLDual.apk can be installed successfully on Android 14 devices.

Bug: 315418422
Change-Id: Iead9ab7b5e6ebe954b6883289aef70cd6d192ad1