Try using a download manager. If not, maybe ask a friend who has faster internet to download it for you. I'm not sure If we're allowed to upload copies of the files since they are covered by copyright etc.

If you really want to try reinstalling the camera application, I think it might be possible as I've seen other posts do it but with other programs, but as others have said, flashing is the fastest and easiest method.

I'm not good with linux at all, but I think the program you need to reinstall would be the "camera-ui". Not sure on the commands of how to reinstall or even uninstall it. Good luck