UPDATE: Implement copy/paste in the UI

base/src/test/user_model/mod.rs

@@ -11,6 +11,7 @@ mod test_keyboard_navigation;
 mod test_on_area_selection;
 mod test_on_expand_selected_range;
 mod test_on_paste_styles;
+mod test_paste_csv;
 mod test_rename_sheet;
 mod test_row_column;
 mod test_styles;