Use the unicode interface by default and return the same value
as before this change.
There are a few locations, that called W->A. It will return the
same value as before for the Ansi version but the unicode one will
now report an error.
--
https://gitlab.winehq.org/wine/wine/-/merge_requests/6481
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v3: winedmo: Introduce a winedmo_stream callback interface for I/O.
winedmo: Use the stream context as a buffer for larger reads.
winedmo: Use the stream context to track stream position.
winedmo: Allocate a client-side stream context with the demuxers.
winedmo: Implement FFmpeg seek and read with user callbacks.
https://gitlab.winehq.org/wine/wine/-/merge_requests/6480
--
v2: winedmo: Introduce a winedmo_stream callback interface for I/O.
winedmo: Use the stream context as a buffer for larger reads.
winedmo: Use the stream context to track stream position.
winedmo: Allocate a client-side stream context with the demuxers.
winedmo: Implement FFmpeg seek and read with user callbacks.
mfsrcsnk: Create a winedmo_demuxer object on the media sources.
https://gitlab.winehq.org/wine/wine/-/merge_requests/6480