Allow partials to be accesed through client

[Aplietexe]

Problem

Currently, the only way to access a partial type to make queries and get it as a return type is to import it from partials directly.

from prisma.partials import PartialUser

res = PartialUser.prisma().find_unique(...)

# res is PartialUser, as we want

however,

from prisma import Prisma

client = Prisma()
await client.connect()

res = client.user.find_unique(...)

# res is User, and there is currently no way to get a PartialUser back

Suggested solution

Allow partials to be accessed through client:

from prisma import Prisma

client = Prisma()
await client.connect()

res = client.partialuser.find_unique(...)

# res is PartialUser

Additional context

This is particularly useful when the prisma client is injected into a function or class for easy testing. It also facilitates the use of the context manager for increased security from errors.