Extract the not-strictly-modes-related parts of ZenModesBackend

So that when it's moved to SettingsLib, it doesn't need to carry that baggage.

Bug: 346519570
Test: atest com.android.settings.notification.modes
Flag: android.app.modes_ui
Change-Id: I7911a521d96f5dbac2c2395171d324b7b54b8b07

src/com/android/settings/notification/modes/ZenModePeopleLinkPreferenceController.java

@@ -34,9 +34,9 @@ class ZenModePeopleLinkPreferenceController extends AbstractZenModePreferenceCon
     private final ZenModeSummaryHelper mSummaryHelper;
 
     public ZenModePeopleLinkPreferenceController(Context context, String key,
-            ZenModesBackend backend) {
+            ZenModesBackend backend, ZenHelperBackend helperBackend) {
         super(context, key, backend);
-        mSummaryHelper = new ZenModeSummaryHelper(mContext, mBackend);
+        mSummaryHelper = new ZenModeSummaryHelper(mContext, helperBackend);
     }
 
     @Override