Update app tests to set Unbundled_build

Based on the description for UnbundledBuildApps(), UnbundledBuild()
should always be true when UnbundledBuildApps() is true.
Updating the test to match this condition.
More details: https://android-review.git.corp.google.com/c/platform/build/soong/+/2380693/comment/54f172b4_2eee54fa/


Bug: b/227460469
Test: m nothing
Change-Id: I3a93edb781522da5af201f6864e157e7bab2195a