fix Telnet#expect (stdlib/telnetlib.pyi)

[pinterior]

telnetlib.Telnet#expect copies given sequence and may modify it. https://github.com/python/cpython/blob/2dc476bcb9142cd25d7e1d52392b73a3dcdf1756/Lib/telnetlib.py#L612-L617
So, when a read-only sequence contains bytes (e.g. tuple of bytes) is passed to expect, TypeError is raised at runtime.

This PR fixes the argument type of the list parameter of Telnet#expect to reject Sequence containing bytes.

I know telnetlib is already removed from stdlib in Python 3.13, but this fix may help users of 3.12 and future users of https://pypi.org/project/standard-telnetlib/ etc.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[JelleZijlstra]

Looks like it only modifies the sequence after copying it (with list[:]), so I don't think we need this change.

Edit: But of course, it does fail later if the slice returns an object of an immutable type. The Sequence API doesn't require slicing to return the same type, though in practice that's what happens. So this change is slightly too restrictive in theory, but seems fine in practice.