text: Title: [BUG] Documents aren't being saved to MongoDB when bulk_writer is used with upsert
  Body: **Describe the bug**
  Documents aren't being saved to MongoDB when bulk_writer is used with upsert.
  
  Using a new DB and collection the following runs without saving anything to the DB.
  
  **To Reproduce**
  pip freeze:
  ```
  annotated-types==0.5.0
  asyncio==3.4.3
  beanie==1.21.0
  click==8.1.6
  dnspython==2.4.1
  lazy-model==0.1.0b0
  motor==3.2.0
  pydantic==2.1.1
  pydantic_core==2.4.0
  pymongo==4.4.1
  toml==0.10.2
  typing_extensions==4.7.1
  ```
  
  
  ```python
  import asyncio
  from beanie import Document, Indexed, init_beanie
  from beanie.odm.bulk import BulkWriter
  from motor.motor_asyncio import AsyncIOMotorClient
  from beanie.operators import Set
  
  
  class User(Document):
      name: Indexed(str)
  
  
  async def example():
      # Beanie uses Motor async client under the hood
      client = AsyncIOMotorClient("mongodb://localhost:27017/BeanieTest")
  
      # Initialize beanie with the Product document class
      await init_beanie(database=client["BeanieBulkWriterUpsetTest"], document_models=[User])
  
      async with BulkWriter() as bulk_writer:
          js = User(name="John Smith")
          await User.find_one(User.name == "John Smith", bulk_writer=bulk_writer).upsert(
              Set({User.name: js.name}), on_insert=js, bulk_writer=bulk_writer
          )
  
  
  if __name__ == "__main__":
      asyncio.run(example())
  
  ```
  
  **Expected behavior**
  If I remove the bulk_writer from `upset(...)` the document is saved to the DB as expected.
  
  ```python
  import asyncio
  from beanie import Document, Indexed, init_beanie
  from beanie.odm.bulk import BulkWriter
  from motor.motor_asyncio import AsyncIOMotorClient
  from beanie.operators import Set
  
  
  class User(Document):
      name: Indexed(str)
  
  
  async def example():
      # Beanie uses Motor async client under the hood
      client = AsyncIOMotorClient("mongodb://localhost:27017/BeanieTest")
  
      # Initialize beanie with the Product document class
      await init_beanie(database=client["BeanieBulkWriterUpsetTest"], document_models=[User])
  
      async with BulkWriter() as bulk_writer:
          js = User(name="John Smith")
          await User.find_one(User.name == "John Smith", bulk_writer=bulk_writer).upsert(
              Set({User.name: js.name}), on_insert=js
          )
  
  
  if __name__ == "__main__":
      asyncio.run(example())
  
  ```
  
  **Additional context**
  Related to #224 
  