prefetch_related with one to one relation doesn't sets backward reference

Describe the bug

For example, you have Parent and Child models, Child holds a OneToOneField reference to a Parent
When you select Parent with .prefetch_related("child"), you can access .child attribute, and it will has prefetched child, as it should be
But when you try to access .parent attribute of that child, it will be QuerySet instead of Parent

To Reproduce

import asyncio

import tortoise

class Parent(tortoise.Model):
    id = tortoise.fields.IntField(pk=True)
    child: tortoise.fields.BackwardOneToOneRelation['Child']

class Child(tortoise.Model):
    parent = tortoise.fields.OneToOneField("app.Parent", related_name="child", pk=True)

async def main():
    await tortoise.Tortoise.init(db_url="sqlite://:memory:", modules={"app": ["__main__"]})
    await tortoise.Tortoise.generate_schemas()
    parent = await Parent.create(id=1)
    await Child.create(parent=parent)
    parent = await Parent.get(id=1).prefetch_related("child")
    print(parent.child) # <Child>
    print(parent.child.parent) # <tortoise.queryset.QuerySet object at ...>

if __name__ == '__main__':
    asyncio.run(main())

Expected behavior

Tortoise sets up a circular references between parent and child models

Additional context

Using latest Tortoise 0.19.3

Start by running the provided asyncio reproduction with Parent, Child, and Parent.get(id=1).prefetch_related("child") to trace how the prefetch_related entry point assigns relations. Check the related OneToOneField and BackwardOneToOneRelation handling. Done means parent.child.parent resolves to the prefetched Parent rather than a QuerySet, with regression coverage for the example.