Use a protected receiver for the keyguard delayed actions

Fixes: 33281221

Test: keyguard locks after the timeout
Test: with test app using code from comment #1, see the following logs
      BroadcastQueue: Permission Denial: broadcasting Intent { act=com.android.internal.policy.impl.PhoneWindowManager.DELAYED_KEYGUARD

Change-Id: I8b6abbc63965a5f0b24a82949ba1925f420a1454