fixed command type, closes #4605

Author: retailcoder

Rubberduck.Core/Navigation/CodeExplorer/CodeExplorerViewModel.cs

@@ -547,7 +547,7 @@ public double FontSize
         public AddTestModuleWithStubsCommand AddTestModuleWithStubsCommand { get; set; }
 		public AddTemplateCommand AddTemplateCommand { get; set; }
         public OpenDesignerCommand OpenDesignerCommand { get; set; }
-        public CommandBase OpenProjectPropertiesCommand { get; set; }
+        public OpenProjectPropertiesCommand OpenProjectPropertiesCommand { get; set; }
         public SetAsStartupProjectCommand SetAsStartupProjectCommand { get; set; }
         public RenameCommand RenameCommand { get; set; }
         public IndentCommand IndenterCommand { get; set; }