Update targetSdk R test apps for PkgSigVerify to use SDK version 30

Android 11 requires that apps targeting R must be signed with at least
the V2 signature scheme. Since the SDK version was not finalized at the
time test apps were created to verify this behavior that targeted SDK
version 'R'. Now that the SDK version is finalized this commit updates
these apps to set the targetSdkVersion to 30 using the build system
where possible.

Fixes: 155946651
Test: atest PkgInstallSignatureVerificationTest
Change-Id: I1a66cc0d3af043137a9a7406e0553e30f0c16201
5 files changed