Allow AOSP processes to read pm_prop

Exclude vendor processes.

Bug: 69309298
Test: cts-tradefed run cts -m CtsCompilationTestCases
    completed in 33s. 5 passed, 0 failed
Test: runtest frameworks-services -c \
    com.android.server.pm.dex.DexoptOptionsTests \
    --install=".*FrameworksServicesTests.apk"
    OK (5 tests)

Change-Id: Ic02caf373e2214b4b931a724ca8d4f4effbc0741