Bluetooth: controller: Fix assert in raising event during proc collision

The fix done in #14938 introduced a later assert when raising an HCI
event for the procedure that was terminated during the procedure
collision handling. This assert happens because the unknown rsp
has information that is needed when raising the event.
Solve this by copying the scratch packet into the node buffer so that
we keep the data.

Fixes #15183

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>