Ignore user-defined __init__/__new__ when calling an enum class - #22195

Fixes part of #16806 (the type-checker problem reported in the comment NOT the stubtest part).

The bug

Calling an enum class looks up a member by value at runtime, through EnumMeta.__call__.
A user-defined __init__ or __new__ only runs while the members are being created. mypy didn't account for this and used the user's constructor signature for the call, so this valid code was rejected:

class Result(enum.StrEnum):
        PASS = enum.auto(), "green"
        def __new__(cls, value: str, color: str) -> Self: ...
        def __init__(self, value: str, color: str) -> None: ...

Result("pass")  # error: Missing positional argument "color"  [call-arg]

The proposed fix

The fix adds a small helper, enum_call_constructor, in mypy/typeops.py.
When an enum defines its own __init__ or __new__, type_object_type uses Enum.__new__(cls, value) for the call signature. Otherwise the existing logic runs unchanged.