Fix settings crashed

Settings keeps crashed when entering the search page since a footer
preference used a system service that isn't found during the indexing
time. Marking a footer preference unsearchable to fix the crash.

Fixes: 276680407
Test: manual test and the settings search should work properly.
Change-Id: If6fada9285bfb30412dea62377577c14353ab0cc
diff --git a/res/xml/security_settings_face.xml b/res/xml/security_settings_face.xml
index f0d0350..9fc8a1f 100644
--- a/res/xml/security_settings_face.xml
+++ b/res/xml/security_settings_face.xml
@@ -80,5 +80,6 @@
 
     <com.android.settingslib.widget.FooterPreference
         android:key="security_face_footer"
+        settings:searchable="false"
         settings:controller="com.android.settings.biometrics.face.FaceSettingsFooterPreferenceController" />
 </PreferenceScreen>