remove pydantic deprecation warning

[hirosassa]

In pytest outputs, there are warnings like below.
I removed two pydantic deprecation warning by replacing dict with model_dump.
ref: https://docs.pydantic.dev/latest/concepts/serialization/#modelmodel_dump

=============================== warnings summary ===============================
tests/api/v1/test_batch_tokenization.py: 10 warnings
  /home/runner/work/konoha/konoha/src/konoha/api/v1/batch_tokenization.py:29: PydanticDeprecatedSince20: The `dict` method is deprecated; use `model_dump` instead. Deprecated in Pydantic V2.0 to be removed in V3.0. See Pydantic V2 Migration Guide at https://errors.pydantic.dev/2.11/migration/
    params = params.dict(exclude={"text", "texts"})

tests/api/v1/test_batch_tokenization.py::test_tokenization[tokenizer_params7]
  /home/runner/work/konoha/konoha/.venv/lib/python3.11/site-packages/nagisa/tagger.py:45: DeprecationWarning: invalid escape sequence '\('
    single_word_list = [w.replace('(', '\(').replace(')', '\)')

tests/api/v1/test_batch_tokenization.py::test_tokenization[tokenizer_params7]
  /home/runner/work/konoha/konoha/.venv/lib/python3.11/site-packages/nagisa/tagger.py:45: DeprecationWarning: invalid escape sequence '\)'
    single_word_list = [w.replace('(', '\(').replace(')', '\)')

tests/api/v1/test_tokenization.py: 11 warnings
  /home/runner/work/konoha/konoha/src/konoha/api/v1/tokenization.py:29: PydanticDeprecatedSince20: The `dict` method is deprecated; use `model_dump` instead. Deprecated in Pydantic V2.0 to be removed in V3.0. See Pydantic V2 Migration Guide at https://errors.pydantic.dev/2.11/migration/
    params = params.dict(exclude={"text", "texts"})

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html

[himkt]

LGTM, thank you!