Implemented Google Play In-App Review.

Commit id-  51336eb,  0db2944,  fdffa0b
from feature/NMCLOUD-832 Implemented Google Play In-App Review.

app/src/main/java/com/nextcloud/client/preferences/AppPreferencesImpl.java

@@ -100,6 +100,7 @@ public final class AppPreferencesImpl implements AppPreferences {
     private static final String PREF__PDF_ZOOM_TIP_SHOWN = "pdf_zoom_tip_shown";
 
     private static final String PREF__STORAGE_PERMISSION_REQUESTED = "storage_permission_requested";
+    private static final String PREF__IN_APP_REVIEW_DATA = "in_app_review_data";
 
     private final Context context;
     private final SharedPreferences preferences;
@@ -118,7 +119,6 @@ public final class AppPreferencesImpl implements AppPreferences {
             this.preferences = preferences;
             this.listeners = new CopyOnWriteArraySet<>();
         }
-        private static final String PREF__IN_APP_REVIEW_DATA = "in_app_review_data";
 
         void add(@Nullable final Listener listener) {
             if (listener != null) {

app/src/main/java/com/nmc/android/app_review/InAppReviewHelperImpl.kt

@@ -109,9 +109,4 @@ class InAppReviewHelperImpl(val appPreferences: AppPreferences) : InAppReviewHel
         const val MIN_APP_RESTARTS_REQ = 10 //minimum app restarts required to ask the review
         const val MAX_DISPLAY_PER_YEAR = 15 //maximum times to ask review in a year
     }
-
 }
-
-
-
-}