Fall back to Wi-Fi data display in data usage screen with no SIM.

Bug: 70950124

Test: manual
Test: make RunSettingsRoboTests
Change-Id: I06bf78e54119819be87e15baca7e5b6a241958cb

src/com/android/settings/SettingsPreferenceFragment.java

@@ -375,7 +375,8 @@ public abstract class SettingsPreferenceFragment extends InstrumentedPreferenceF
         return mPreferenceCache != null ? mPreferenceCache.size() : 0;
     }
 
-    protected boolean removePreference(String key) {
+    @VisibleForTesting(otherwise = VisibleForTesting.PROTECTED)
+    public boolean removePreference(String key) {
         return removePreference(getPreferenceScreen(), key);
     }