[Windows] Always get the non-truncated face name in the style editor and in the font picker

[moi15moi]

On Windows, wxFontEnumerator::GetFacenames and wxFont::GetFaceName use GDI, which truncates the face name to 31 characters. This PR affects the font selection in the style editor and in the font picker.

Because of this, some users like in https://github.com/libass/libass/issues/710 may think they have retrieved the correct face name, but that is not the case.

Tested on Windows 7 (Version 6.1.7601) and Windows 10 (Version 10.0.19045.4780).