[AAPM] CTS tests for Disallow Install Unknown Sources

To minimize code duplication, this change also creates a
BaseAdvancedProtectionTest class.

Bug: 369361373
Test: atest AdvancedProtectionManagerTest
Test: atest AdvancedProtectionServiceTest
Test: atest DisallowInstallUnknownSourcesTest
Flag: android.security.aapm_feature_disable_install_unknown_sources
Change-Id: I4d2c8b19e8fb754be705f544df7165af98fe1756
3 files changed