fix(typing): Resolve all `mypy` & `pyright` errors for `_arrow` #6629

Job	Run time
pytest-38 (3.8, windows-latest)	1m 14s
pytest-38 (3.8, ubuntu-latest)	48s
pytest-full-coverage (3.11, ubuntu-latest)	5m 30s
pytest-full-coverage (3.13, ubuntu-latest)	4m 15s
pytest-windows (3.10, windows-latest)	4m 26s
pytest-windows (3.12, windows-latest)	5m 7s
	21m 20s

Provide feedback