Filter out SecuritySettings search results when alternative available.

When alternative fragment is shown for the security settings page, we
don't want to show search results that would lead to an unused security
settings page.

Test: manual
Test: atest SettingsUnitTests
Test: make RunSettingsRoboTests -j
Bug: 184613149
Change-Id: I525bd87d1ac6a24a7a26f59ae917e35ac39732e3