Add role guarded APIs for subscribing to keyguard locked state in KeyguardManager.

Bug: 216630470
CTS-Coverage-Bug: 220371902
Test: manual
Test: atest CtsAppTestCases:KeyguardLockedStateApiTest
Ignore-AOSP-First: (for packages/Shell/AndroidManifest.xml) Permission
not yet publicly announced.

Change-Id: I1f44ec6799b0f74791613389ce28aadf84c9fe5c