Remove the dataclasses third-party stub (#8216)

dataclasses is part of the Python stdlib and the third-party package is
not supported past Python 3.6.

stubs/dataclasses/@tests/stubtest_allowlist.txt

@@ -1,5 +0,0 @@
-dataclasses.Field.__init__
-dataclasses.InitVar.__init__
-dataclasses.dataclass
-dataclasses.field
-dataclasses.replace

stubs/dataclasses/METADATA.toml

@@ -1,2 +0,0 @@
-version = "0.6"
-no_longer_updated = true

stubs/dataclasses/dataclasses.pyi

@@ -1,92 +0,0 @@
-import sys
-from collections.abc import Callable, Iterable, Mapping
-from typing import Any, Generic, TypeVar, overload
-
-if sys.version_info >= (3, 9):
-    from types import GenericAlias
-
-_T = TypeVar("_T")
-
-class _MISSING_TYPE: ...
-
-MISSING: _MISSING_TYPE
-
-@overload
-def asdict(obj: Any) -> dict[str, Any]: ...
-@overload
-def asdict(obj: Any, *, dict_factory: Callable[[list[tuple[str, Any]]], _T]) -> _T: ...
-@overload
-def astuple(obj: Any) -> tuple[Any, ...]: ...
-@overload
-def astuple(obj: Any, *, tuple_factory: Callable[[list[Any]], _T]) -> _T: ...
-@overload
-def dataclass(_cls: type[_T]) -> type[_T]: ...
-@overload
-def dataclass(_cls: None) -> Callable[[type[_T]], type[_T]]: ...
-@overload
-def dataclass(
-    *, init: bool = ..., repr: bool = ..., eq: bool = ..., order: bool = ..., unsafe_hash: bool = ..., frozen: bool = ...
-) -> Callable[[type[_T]], type[_T]]: ...
-
-class Field(Generic[_T]):
-    name: str
-    type: type[_T]
-    default: _T
-    default_factory: Callable[[], _T]
-    repr: bool
-    hash: bool | None
-    init: bool
-    compare: bool
-    metadata: Mapping[str, Any]
-    if sys.version_info >= (3, 9):
-        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
-
-# NOTE: Actual return type is 'Field[_T]', but we want to help type checkers
-# to understand the magic that happens at runtime.
-@overload  # `default` and `default_factory` are optional and mutually exclusive.
-def field(
-    *,
-    default: _T,
-    init: bool = ...,
-    repr: bool = ...,
-    hash: bool | None = ...,
-    compare: bool = ...,
-    metadata: Mapping[str, Any] | None = ...,
-) -> _T: ...
-@overload
-def field(
-    *,
-    default_factory: Callable[[], _T],
-    init: bool = ...,
-    repr: bool = ...,
-    hash: bool | None = ...,
-    compare: bool = ...,
-    metadata: Mapping[str, Any] | None = ...,
-) -> _T: ...
-@overload
-def field(
-    *, init: bool = ..., repr: bool = ..., hash: bool | None = ..., compare: bool = ..., metadata: Mapping[str, Any] | None = ...
-) -> Any: ...
-def fields(class_or_instance: Any) -> tuple[Field[Any], ...]: ...
-def is_dataclass(obj: Any) -> bool: ...
-
-class FrozenInstanceError(AttributeError): ...
-
-class InitVar(Generic[_T]):
-    if sys.version_info >= (3, 9):
-        def __class_getitem__(cls, type: Any) -> GenericAlias: ...
-
-def make_dataclass(
-    cls_name: str,
-    fields: Iterable[str | tuple[str, type] | tuple[str, type, Field[Any]]],
-    *,
-    bases: tuple[type, ...] = ...,
-    namespace: dict[str, Any] | None = ...,
-    init: bool = ...,
-    repr: bool = ...,
-    eq: bool = ...,
-    order: bool = ...,
-    unsafe_hash: bool = ...,
-    frozen: bool = ...,
-) -> type: ...
-def replace(obj: _T, **changes: Any) -> _T: ...