Avoid copying buffer twice
Summary:
Previously we copied frames first to a temporary QImage and then to PipeWire buffer. This shouldn't be
necessary as we can copy frames directly to PipeWire buffers which should be much more effecient.
BUG: 419209
Reviewers: Plasma, zzag
Reviewed By: Plasma, zzag
Subscribers: meven, zzag, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D28272