🏷️ Allow AliasChoices and AliasPath for validation_alias in Field

[YuriiMotov]

This PR updates type hints for validation_alias parameter of Field to be in line with Pydantic's version:

    validation_alias: str | AliasPath | AliasChoices | None = _Unset,

Also, added tests for AliasPath and AliasChoices

---

The following code works on master:

from typing import Optional

from pydantic import AliasChoices, AliasPath
from sqlmodel import Field, SQLModel


class User(SQLModel):
    first_name: str = Field(validation_alias="firstName", serialization_alias="f_name")
    second_name: Optional[str] = Field(
        default=None, validation_alias=AliasChoices("secondName", "surname")
    )
    nickname: Optional[str] = Field(
        default=None, validation_alias=AliasPath("names", 2)
    )


test_data = [
    {"firstName": "John", "secondName": "Doe", "names": ["John", "Doe", "Johnny"]},
    {"firstName": "John", "surname": "Doe", "names": ["John", "Doe", "Johnny"]},
]


for data in test_data:
    print(User.model_validate(data))

# first_name='John' second_name='Doe' nickname='Johnny'
# first_name='John' second_name='Doe' nickname='Johnny'

.. but mypy argues with:

main.py:9: error: No overload variant of "Field" matches argument types "None", "AliasChoices"  [call-overload]
main.py:12: error: No overload variant of "Field" matches argument types "None", "AliasPath"  [call-overload]

This PR fixes this.