Fix previous cherry-picked TileMapEitorPlugin change

That part of a3622701127daf4172ad4c9ac9f04fc493ae14bd was specific to the master branch.

editor/plugins/tile_map_editor_plugin.cpp

@@ -51,8 +51,6 @@ void TileMapEditor::_notification(int p_what) {
 			rotate_180->set_icon(get_icon("Rotate180", "EditorIcons"));
 			rotate_270->set_icon(get_icon("Rotate270", "EditorIcons"));
 
-			search_box->add_icon_override("right_icon", get_icon("Search", "EditorIcons"));
-
 		} break;
 
 		case EditorSettings::NOTIFICATION_EDITOR_SETTINGS_CHANGED: {