FastAPI schema can not show the fields in parent odmantic.Model class

# Bug

```python
# odmantic model
class User(odmantic.Model):
username: str
password: str

# model in fastapi for response
class CurrentUser(User):
token: str

class LoginForm(pydantic.Model):
username: str = pydantic.Field(description="Username")
password: str = pydantic.Field(description="Password")

@router.post("/login", description="Method to login user",
response_model=CurrentUser,
response_model_exclude_none=True)
async def login(request: Request, db: AsyncEngine = Depends(get_engine), form = Body()) -> CurrentUser {
...
}

```

### Current Behavior

The response model in FastAPI swagger for CurrentUser only has the `token` field, `username` and `password` in parent class is missing.

### Expected behavior

The response model in FastAPI swagger for CurrentUser should contains `username`, `password` and `token`.

### Environment

- ODMantic version: 0.9.2
- MongoDB version: ...
- Pydantic infos (output of `python -c "import pydantic.utils; print(pydantic.utils.version_info())`):

pydantic version: 1.10.9
pydantic compiled: True
install path: ...
python version: 3.11.3 (main, Apr 7 2023, 20:13:31) [Clang 14.0.0 (clang-1400.0.29.202)]
platform: macOS-13.4-arm64-arm-64bit
optional deps. installed: ['typing-extensions']

- Version of additional modules (if relevant):
- ...

**Additional context**

Use the issue's User and CurrentUser models and the @router.post response_model example as the reproduction entry point. Inspect how ODMantic.Model inheritance is converted for FastAPI schema generation, then compare the generated Swagger response schema. Done means the schema for CurrentUser includes username, password, and token.

Written by the indexing model from the issue text.