Draft: vulkan: compute return from process on invalid buffer id
requested to merge columbarius/pipewire:columbarius/vulkan-compute-fix-invalid-buffer-id into master
[WIP]
Combined with the blit filter the process function of the source is often called without a valid buffer, which results in a crash. This hack mitigates this.
MR opened to track the issue. Probably this should be catched in the PipeWire spa_node and not in the vulkan part.