kiosk: Extract KioskSettingsTest from KioskDeviceOwnedTest

Here are the tests extracted:

KioskDeviceOwnedTest, SettingsWindow
  ==> KioskSettingsTest, CanNavigateToSettingsUrl
  ==> KioskSettingsTest, CanNavigateToSettingsSubUrl
  ==> KioskSettingsTest, CannotNavigateToNonSettingsUrl
  ==> KioskSettingsTest, CannotNavigateToDisallowedSubUrl
  ==> KioskSettingsTest, DoesNotOpenTwoSettingsBrowsers
  ==> KioskSettingsTest,
      NavigatingToSettingsInAppCreatesNewBrowser
  ==> KioskSettingsTest,
      SettingsBrowserIsNullWhenSettingsIsClosed

KioskDeviceOwnedTest, SettingsWindowShouldBeActive
  ==> KioskSettingsTest, CanRefocusSettings

KioskDeviceOwnedTest, SettingsWindowRemainsOpen
KioskDeviceOwnedTest, CloseSettingsWindow
  ==> deleted in favor of pre-existing tests:
      KioskTest, ExitsIfOnlySettingsWindowRemainsOpen
      KioskTest, DoesNotExitWhenSettingsWindowCloses

Bug: 379246208
Test: testing/xvfb.py tools/autotest.py -C out/Default chrome/browser/ash/app_mode/test/kiosk_settings_browsertest.cc chrome/browser/ash/login/app_mode/test/kiosk_device_owned_browsertest.cc
Change-Id: I9fd5212298268700906d372cd7204144fd19bcef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6088910
Reviewed-by: Polina Bondarenko <pbond@chromium.org>
Commit-Queue: Edman Anjos <edman@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1396768}