Update toggle text for Data Saver

Update Data Saver toggle to say "Use Data Saver" instead of "On"/"Off"

Bug: 75983536
Test: Robotest, manual test and atest DataSaverSummaryUITest
Change-Id: Icf690638570278fb869515931943ac486adbfc7c

src/com/android/settings/datausage/DataSaverSummary.java

@@ -68,6 +68,9 @@ public class DataSaverSummary extends SettingsPreferenceFragment
     public void onActivityCreated(Bundle savedInstanceState) {
         super.onActivityCreated(savedInstanceState);
         mSwitchBar = ((SettingsActivity) getActivity()).getSwitchBar();
+        mSwitchBar.setSwitchBarText(
+                R.string.data_saver_switch_title,
+                R.string.data_saver_switch_title);
         mSwitchBar.show();
         mSwitchBar.addOnSwitchChangeListener(this);
     }