New crash since 24.9.5

[Zac-HD]

from contextlib import asynccontextmanager

@asynccontextmanager
async def fn():
    async with a().b():
        yield

crashes with

...
  File ".../python3.11/site-packages/flake8_async/visitors/visitor91x.py", line 522, in visit_With_body
    self._checkpoint_with(node)
  File ".../python3.11/site-packages/flake8_async/visitors/visitor91x.py", line 511, in _checkpoint_with
    assert func is not None
           ^^^^^^^^^^^^^^^^
AssertionError

in 24.11.1; fine in 24.9.5