[plugin-prisma] Support filtering on totalCount for relationCount

[P4sca1]

Once the feature is available in prisma. This is currently planned for Prisma 4.1. https://github.com/prisma/prisma-engines/pull/3057

[hayes]

This will be very helpful. I think it will probably need to be behind a flag until the next major, but should be straightforward to support (but maybe a little complicated)