Stop search tests using location_settings

Stop robolectric search tests using location_settings, use
sound_settings instead.

The choice of location_settings.xml seems arbitrary, and there's a
commit coming which means one of the controllers doesn't just use
settings to check availability. When the unconfigured mock returns null
from a method, that causes the test to fail in a non-obvious way.

Bug: 171371424
Test: m RunSettingsRoboTests
Change-Id: I4d3386e3c62fb4151e4a4e27625edccec89316d9
diff --git a/tests/robotests/src/com/android/settings/testutils/FakeIndexProvider.java b/tests/robotests/src/com/android/settings/testutils/FakeIndexProvider.java
index c961559..910ca54 100644
--- a/tests/robotests/src/com/android/settings/testutils/FakeIndexProvider.java
+++ b/tests/robotests/src/com/android/settings/testutils/FakeIndexProvider.java
@@ -30,7 +30,7 @@
     public static final String KEY = "TestKey";
 
     public static final BaseSearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
-            new BaseSearchIndexProvider(R.xml.location_settings) {
+            new BaseSearchIndexProvider(R.xml.sound_settings) {
 
                 @Override
                 public List<String> getNonIndexableKeys(Context context) {