[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