remove unused variables

Signed-off-by: alperozturk <alper_ozturk@proton.me>

Author: alperozturk96

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

@@ -103,7 +103,6 @@ public final class AppPreferencesImpl implements AppPreferences {
     private static final String PREF__IN_APP_REVIEW_DATA = "in_app_review_data";
 
     private static final String PREF__TWO_WAY_STATUS = "two_way_sync_status";
-    private static final String PREF__RESET_TWO_WAY_SYNC_TIMESTAMP = "reset_two_way_sync_timestamp";
     private static final String PREF__TWO_WAY_SYNC_INTERVAL = "two_way_sync_interval";
 
     private static final String LOG_ENTRY = "log_entry";