[3.8] bpo-46400: Update libexpat from 2.4.1 to 2.4.4 (GH-31022)

[corona10]

https://bugs.python.org/issue46400

[dil022dixith]

When can we expect this will merged and available for 3.8 Version.

[corona10]

@dil022dixith It's up to @ambv :)

[ambv]

I'm fine with merging this to 3.8 and releasing, however, there's already 2.4.6 out:
https://bugs.python.org/issue46794

[corona10]

@ambv cc @ned-deily
I would like to request merging this PR anyway since the main branch is already merged.
And for better diff comparison when upgrading libexpat, this way will be more convenient.

[ambv]

@corona10 fair enough!

[corona10]

Thanks!