fix: handle grouped profile experiences in get_profile_experiences

The fix is related to the issue [451](https://github.com/tomquirk/linkedin-api/issues/451) When dealing with grouped experiences (e.g. multiple positions at the same company) the API response will contain multiple indexes in data["included"]. The index with the most elements will contain probably all experiences, both grouped and individual, while other indexes may only contain partial data for the grouped experiences. Therefore, we want to use the index with the most items to ensure we process all experiences. I tested it on two large profile (14 and 8 experiences) with grouped experiences