Add missing check in getKeyguardDisabledFeature

Add check that if admin package is specified, it belong to the calling
admin.

Bug: 193663287
Test: atest com.android.cts.devicepolicy.MixedDeviceOwnerTest
      #testSetKeyguardDisabledFeatures
      atest com.android.cts.devicepolicy.MixedProfileOwnerTest
      #testSetKeyguardDisabledFeatures
      atest com.android.cts.devicepolicy.MixedManagedProfileOwnerTest
      #testSetKeyguardDisabledFeatures
      atest ManagedProfileTest#testDevicePolicyManagerParentSupport

Change-Id: I107d8705e3a65707ae5744e7705a4d32629c3c14