chroma: chain: handle resize converter fmt changes
This fixes the transform filter from the chain converter. Consequently, this
fixes transform filters with HW decoders.
Recent improvements in copy_cache_t allow to have correct performances for most
use cases. This is far from perfect, but doing 4K HW decoding and SW transform
is slightly better than doing 4K SW decoding and SW transform (tested on
Linux/Windows).
Obviously, the best solution is to do this transformation with shaders. This
will be possible in VLC 4.0 with future gl/d3d filters API.
Fixes #19096