`Literal[False, True]` is not assignable to `bool`, sometimes

### Describe the Bug

`pyright` and `ty` accept both versions, but `pyrefly` complains if there was an assignment before passing the argument to the function:

```py
from typing import Literal

def func(_mapping: dict[str, str | bool]) -> None:
return

def example(a: Literal[True], b: Literal[False], c: str) -> None:
ok = func({"a": a, "b": b, "c": c})
infer = {"a": a, "b": b, "c": c}
nope = func(infer) # Argument `dict[str, Literal[False, True] | str]` is not assignable to parameter `_mapping` with type `dict[str, bool | str]` in function `func` [bad-argument-type]
```

I took a look at the typing spec, and I didn't find anything specifying my expectation.
The closest was here:
- https://typing.python.org/en/latest/spec/literal.html#interactions-with-enums-and-exhaustiveness-checks
- https://typing.python.org/en/latest/spec/literal.html#interactions-with-narrowing

Essentially I'd expect `Literal[False, True]` to be assignable to `bool` - in the same way that `Literal[, ...]` is assignable to ``

### Sandbox Link

https://pyrefly.org/sandbox/?project=v2.pZTBDoIwDIZfZZEDmBB35wE8excOY0wkmo3A8GJ8d_92EAUTovHWNO2frf36_2CZo-u9Y5pgSewZmajgXnRojBFgLXHcxXL_AalJwYRDTFQ2aR9pX0UqyldmrwAdUppveynoLpgKv-SebxRYESrFlEqKSoo0RfoBIPhI7Ml06FgvDrXWtbQYFue-7efGI3EICTEOD14HVOoBjgoEdrmNYKZGnL1v-0zKqd11tTRWVk73ctYhBcGtbqphn57LCceE9pD9B7U4kBavgRYTZ6jAlwfrG3811RcwPQE

### Additional Info
The repro is based on (https://github.com/dangotbanned/mosaic/blob/f24c14ed921794cb5db3712ab626d694c5501c00/packages/vgplot/spec-python/tools/codegen/typed_dict.py#L51-L80).
Where I tried out `pyrefly` on a new codebase and this error was reported twice

Start with the Python example in the issue and reproduce it in the linked pyrefly sandbox, comparing the direct dictionary argument with the assigned `infer` variable. Review the referenced `packages/vgplot/spec-python/tools/codegen/typed_dict.py` context and the typing-spec links; done means the assigned dictionary containing `Literal[False, True]` is accepted as `dict[str, str | bool]` without regressing related checks.

Written by the indexing model from the issue text.