Use source stamp app targeting SDK version 29

The modified app would fix source stamp tests running on master, which
otherwise gives the following error:

Targeting S+ (version 10000 and above) requires that an explicit value
for android:exported be defined when intent filters are present

Bug: 158443829
Test: atest FrameworksServicesTests:AppIntegrityManagerServiceImplTest
Change-Id: Ia41bb0c3c90bbc96bdfaa6e336dbbc2ce6077a7f