feat: resize elements from the sides (#7855)

Co-authored-by: dwelle <5153846+dwelle@users.noreply.github.com>

packages/excalidraw/groups.ts

@@ -387,3 +387,7 @@ export const elementsAreInSameGroup = (elements: ExcalidrawElement[]) => {
 
   return maxGroup === elements.length;
 };
+
+export const isInGroup = (element: NonDeletedExcalidrawElement) => {
+  return element.groupIds.length > 0;
+};