Fix invalid escape sequence by using raw string

Resolve warnings in test output by addressing escape sequence issues.
- actions log

=============================== warnings summary ===============================
../../home/apl/.pyenv/versions/3.12.2/lib/python3.12/site-packages/pydantic/fields.py:804
  /home/apl/.pyenv/versions/3.12.2/lib/python3.12/site-packages/pydantic/fields.py:804: PydanticDeprecatedSince20: Using extra keyword arguments on `Field` is deprecated and will be removed. Use `json_schema_extra` instead. (Extra keys: 'nullable'). Deprecated in Pydantic V2.0 to be removed in V3.0. See Pydantic V2 Migration Guide at https://errors.pydantic.dev/2.7/migration/
    warn(

tests/app/token_TransferHistory_test.py:950
  /app/ibet-Wallet-API/tests/app/token_TransferHistory_test.py:950: PytestUnknownMarkWarning: Unknown pytest.mark.aysincio - is this a typo?  You can register custom marks to avoid this warning - for details, see https://docs.pytest.org/en/stable/how-to/mark.html
    @pytest.mark.aysincio

tests/app/token_TransferHistory_test.py::TestTokenTransferHistory::test_normal_4_8[2023-11-06T23:00:00+09:00]
  tests/app/token_TransferHistory_test.py:1019: PytestWarning: The test <Function test_normal_4_8[2023-11-06T23:00:00+09:00]> is marked with '@pytest.mark.asyncio' but it is not an async function. Please remove the asyncio mark. If the test is not marked explicitly, check for global marks applied via 'pytestmark'.
    @pytest.mark.asyncio

tests/app/token_TransferHistory_test.py::TestTokenTransferHistory::test_normal_4_8[2023-11-06T14:00:00+00:00]
  tests/app/token_TransferHistory_test.py:1019: PytestWarning: The test <Function test_normal_4_8[2023-11-06T14:00:00+00:00]> is marked with '@pytest.mark.asyncio' but it is not an async function. Please remove the asyncio mark. If the test is not marked explicitly, check for global marks applied via 'pytestmark'.
    @pytest.mark.asyncio

tests/migrations/downgrade_test.py::TestMigrationsDowngrade::test_downgrade_from_v23_6
  /app/ibet-Wallet-API/migrations/env.py:131: SyntaxWarning: invalid escape sequence '\)'
    new_line = re.sub("\)$", ", schema=get_db_schema())", line)

tests/migrations/downgrade_test.py::TestMigrationsDowngrade::test_downgrade_from_v23_6
  /app/ibet-Wallet-API/migrations/env.py:133: SyntaxWarning: invalid escape sequence '\)'
    new_line = re.sub("schema=(.)*\)$", "schema=get_db_schema())", line)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
------------- generated xml file: /app/ibet-Wallet-API/pytest.xml --------------

File	Stmts	Miss	Cover	Missing
schema
position.py	143	0	100%
schema/base
base.py	56	4	92%	63, 69–71
TOTAL	11053	1047	90%

BoostryJP / ibet-Wallet-API

Fix invalid escape sequence by using raw string #1548