setAutoTimeRequired disabled on managed profile

* A security exception should be thrown when
  setAutoTimeRequired is called on a managed profile
* Update javadoc

Bug: 156620695
Test: atest com.android.server.devicepolicy.DevicePolicyManagerTest
      atest com.android.cts.devicepolicy.MixedDeviceOwnerTest#testSetAutoTimeRequired
      atest com.android.cts.devicepolicy.MixedProfileOwnerTest#testSetAutoTimeRequired
      atest com.android.cts.devicepolicy.MixedManagedProfileOwnerTest#testSetAutoTimeRequired
Change-Id: Ifb53c218947f62aa446aa607d3f4eee354586395