Update MSBDAReader::process for DPBuffer
MSBDAReader supports processing DPBuffer (and not BDABuffer) since DP3 always passes a DPBuffer to the first step.
-> Ensure that MSBDAReader::process works with std::unique_ptr
MSBDAReader supports processing DPBuffer (and not BDABuffer) since DP3 always passes a DPBuffer to the first step.
-> Ensure that MSBDAReader::process works with std::unique_ptr