Return buffer to pipewire when returning early from recordFrame
Summary: Even when something goes wrong, the buffer should be returned to pipewire for recycling on next frame.
Test Plan:
Before: when something goes wrong when screencasting, first errors are the actual issue and subsequent errors are due to pipewire not having any buffers for the pw_stream_deque_buffer call
After: when something goes wrong when screencasting, errors are always the actual issue
Reviewers: Plasma, jgrulich
Reviewed By: jgrulich
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D28713