Fix sheet pin import after SelectPoint API change

Fixes https://gitlab.com/kicad/code/kicad/-/issues/4552

eeschema/tools/ee_selection_tool.cpp

@@ -541,12 +541,12 @@ bool EE_SELECTION_TOOL::SelectPoint( const VECTOR2I& aWhere, const KICAD_T* aFil
             if( aSubtract || ( aExclusiveOr && collector[i]->IsSelected() ) )
             {
                 unselect( collector[i] );
-                anySubtracted = false;
+                anySubtracted = true;
             }
             else
             {
                 select( collector[i] );
-                anySubtracted = true;
+                anyAdded = true;
             }
         }
     }

eeschema/tools/sch_drawing_tools.cpp

@@ -816,8 +816,13 @@ int SCH_DRAWING_TOOLS::TwoClickPlace( const TOOL_EVENT& aEvent )
                 case SCH_SHEET_PIN_T:
                 {
                     SCH_HIERLABEL* label = nullptr;
-                    SCH_SHEET*     sheet = (SCH_SHEET*) m_selectionTool->SelectPoint( cursorPos,
-                                                                       EE_COLLECTOR::SheetsOnly );
+                    SCH_SHEET*     sheet = nullptr;
+
+                    if( m_selectionTool->SelectPoint( cursorPos, EE_COLLECTOR::SheetsOnly, &item ) )
+                        sheet = dynamic_cast<SCH_SHEET*>( item );
+
+                    item = nullptr;
+
                     if( !sheet )
                     {
                         m_statusPopup.reset( new STATUS_TEXT_POPUP( m_frame ) );