[Pylint] Fixed false-positive on the rule PLW1641 (eq-without-hash)

[boolean-light]

Summary

Fixed false-positive on the rule PLW1641, where the explicit assignment on the __hash__ method is not counted as an definition of __hash__. (Discussed in #10557).

Also, added one new testcase.

Test Plan

Checked on cargo test in eq_without_hash.py.

Before the change, for the assignment into __hash__, only __hash__ = None was counted as an explicit definition of __hash__ method.
Probably any assignment into __hash__ property could be counted as an explicit definition of hash, so I removed value.is_none_literal_expr() check.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+1 -11 violations, +0 -0 fixes in 3 projects; 41 projects unchanged)

pandas-dev/pandas (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --preview

- pandas/core/dtypes/dtypes.py:947:7: PLW1641 Object does not implement `__hash__` method

python/typeshed (+0 -10 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --preview --select E,F,FA,I,PYI,RUF,UP,W

- stdlib/io.pyi:17:5: F822 Undefined name `BufferedRWPair` in `__all__`
- stdlib/io.pyi:18:5: F822 Undefined name `BufferedRandom` in `__all__`
- stdlib/io.pyi:19:5: F822 Undefined name `BufferedReader` in `__all__`
- stdlib/io.pyi:20:5: F822 Undefined name `BufferedWriter` in `__all__`
- stdlib/io.pyi:25:5: F822 Undefined name `StringIO` in `__all__`
- stdlib/io.pyi:26:5: F822 Undefined name `TextIOBase` in `__all__`
- stdlib/io.pyi:27:5: F822 Undefined name `TextIOWrapper` in `__all__`
- stdlib/io.pyi:34:40: F822 Undefined name `IncrementalNewlineDecoder` in `__all__`
- stdlib/io.pyi:34:69: F822 Undefined name `text_encoding` in `__all__`
- stdlib/io.pyi:36:1: PYI018 Private TypeVar `_T` is never used

rotki/rotki (+1 -0 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --preview

+ rotkehlchen/history/events/structures/evm_event.py:63:36: RUF100 [*] Unused `noqa` directive (unused: `PLW1641`)

Changes by rule (4 rules affected)

code	total	+ violation	- violation	+ fix	- fix
F822	9	0	9	0	0
RUF100	1	1	0	0	0
PLW1641	1	0	1	0	0
PYI018	1	0	1	0	0

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

[charliermarsh]

Thanks!