bug6214: Remove unused field and imports after selection model refactoring

Removed:
- Unused HandlerRegistration import
- Unused MultiSelectionModel import
- Unused leaderboardAsTableSelectionModelRegistration field and its assignment
- Updated Javadoc for selectionChangeHandler to remove reference to removed field

java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/leaderboard/LeaderboardPanel.java

@@ -29,7 +29,6 @@ import com.google.gwt.dom.client.Style.FontWeight;
 import com.google.gwt.dom.client.Style.Unit;
 import com.google.gwt.event.dom.client.ClickEvent;
 import com.google.gwt.event.dom.client.ClickHandler;
-import com.google.gwt.event.shared.HandlerRegistration;
 import com.google.gwt.i18n.client.NumberFormat;
 import com.google.gwt.resources.client.ImageResource;
 import com.google.gwt.safecss.shared.SafeStyles;
@@ -55,7 +54,6 @@ import com.google.gwt.user.client.ui.SimplePanel;
 import com.google.gwt.user.client.ui.Widget;
 import com.google.gwt.view.client.CellPreviewEvent;
 import com.google.gwt.view.client.ListDataProvider;
-import com.google.gwt.view.client.MultiSelectionModel;
 import com.google.gwt.view.client.SelectionChangeEvent;
 import com.google.gwt.view.client.SelectionChangeEvent.Handler;
 import com.sap.sse.gwt.client.celltable.RefreshableMultiSelectionModel;
@@ -326,20 +324,10 @@ public abstract class LeaderboardPanel<LS extends LeaderboardSettings> extends A
     private Button filterClearButton;
 
     /**
-     * The handler for changes in the leaderboard table's selection; its registration is kept in
-     * {@link #leaderboardAsTableSelectionModelRegistration} while it is registered as a selection handler on the
-     * {@link #leaderboardTable}.
+     * The handler for changes in the leaderboard table's selection.
      */
     private final Handler selectionChangeHandler;
 
-    /**
-     * While the {@link #selectionChangeHandler} is registered as a selection change handler on the
-     * {@link #leaderboardTable}'s selection model, this field holds the registration which can be used to remove the
-     * registration again. We'll use this to temporarily suspend selection events when actively modifying / adjusting
-     * the table selection to match the {@link #competitorSelectionProvider}.
-     */
-    private HandlerRegistration leaderboardAsTableSelectionModelRegistration;
-
     /**
      * Guard flag to prevent infinite recursion when synchronizing selection state between the selection model
      * and the CompetitorSelectionProvider. Set to true when we're updating the selection model in response to
@@ -556,8 +544,7 @@ public abstract class LeaderboardPanel<LS extends LeaderboardSettings> extends A
                 }
             }
         };
-        leaderboardAsTableSelectionModelRegistration = leaderboardSelectionModel
-                .addSelectionChangeHandler(selectionChangeHandler);
+        leaderboardSelectionModel.addSelectionChangeHandler(selectionChangeHandler);
         leaderboardTable.setSelectionModel(leaderboardSelectionModel, selectionCheckboxColumn.getSelectionManager());
 
         SimplePanel mainPanel = new SimplePanel();