Try enabling 10bit pixel formats in x265

[tanersener]

See the original issue reported in flutter_ffmpeg.

We don't know if enabling 10 bit support is possible. We must test and see this feature.

[tanersener]

Fixed on the development branch. Validated that yuv420p10le pixel format is enabled when x265 is built with 10bit support.

Video: hevc (Main 10) (hev1 / 0x31766568), yuv420p10le(tv, bt2020nc/bt2020/arib-std-b67, progressive), 1080x1920, 4374 kb/s, 30 fps, 30 tbr, 15360 tbn, 30 tbc (default)