[`flake8-pytest-style`] Fix defaults when `lint.flake8-pytest-style` config section is empty (`PT001`, `PT023`) #33783

Job	Run time
python package	1m 18s
cargo fmt	23s
Determine changes	8s
mkdocs	2m 35s
pre-commit	43s
cargo test (windows)	8m 15s
cargo test (linux)	3m 58s
cargo clippy	1m 45s
cargo build (release)	4m 29s
cargo build (msrv)	3m 11s
cargo test (wasm)	1m 30s
test scripts	1m 1s
benchmarks	5m 12s
cargo fuzz	4m 47s
cargo shear	23s
formatter instabilities and black similarity	0s
test ruff-lsp	21s
ecosystem	9m 15s
Fuzz the parser	0s
	49m 14s

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