For Discusssion: Add comfiguration for Max MMS Size?

Hello!

I was working to figure out an issue with MMS that turned out to be that the maximum attachment size is way to big for a given carrier.

https://cs.android.com/android/platform/superproject/+/master:packages/apps/CarrierConfig/assets/

This shows on some carriers that they have a max attachment size. Would you all be opposed to including this in m-b-p-i? If so, I can add it.