feat: allow inner-drag-selecting with cmd/ctrl (#3603)

* feat: allow inner-drag-selecting with cmd/ctrl

* don't use  cursor when pressing cmd/ctrl

* ensure we reset deselected groups

* add tests

* add docs

* couple fixes around group selection

src/tests/zindex.test.tsx

@@ -56,9 +56,8 @@ const populateElements = (
         y,
         width,
         height,
+        groupIds,
       });
-      // @ts-ignore
-      element.groupIds = groupIds;
       if (isSelected) {
         selectedElementIds[element.id] = true;
       }