Windows openxr loader UTF8 path read error

Hello，i found openxr loader got an error when read runtime path from windows regedit which contains chinese word。

1. xr loader turn wider char to utf8 after read runtime path from regedit:

2. below is utf8 string：

3. xr loader turn back to wide char when try to check file if exists:

4. xr check file ok, then store the path in the list with utf8 format:

5. got error when try to load file with utf8 formated path，std::ifstream could not recognize utf8 string:

Trace the Windows runtime-path handling from the registry read through the UTF-8 and wide-character conversions described in the report, focusing on the final std::ifstream load. Reproduce the problem with a registry path containing Chinese characters. Done means the runtime file loads successfully when its path contains non-ASCII characters.

Written by the indexing model from the issue text.