Hide keyguard lock icon when QS user icon enabled

Test: Build with config_keyguard_user_switch_opens_qs_details=true and
      config_keyguardUserSwitcher=true, check that there is no lock icon
      on keyguard.
Test: Build with config_keyguard_user_switch_opens_qs_details=false and
      config_keyguardUserSwitcher=false, check that there is a lock icon
      on keyguard.
Test: atest SystemUITests:com.android.systemui.statusbar.phone.LockscreenIconControllerTest

Bug: 181235684
Change-Id: Ic81ef56eb0caf297d1078447b9b749c2b504a1e9