zink: fix broken pool-alloc consolidation
When appending the content of a util_dynarray to another util_dynarray, we need to copy the content to the end of the util_dynarray, not the beginning.
As we've already resized the dynarray, We also shouldn't add to the size once more at the end, otherwise we'll end up with garbage.
Fixes: 43dcdf33 ("zink: rework/improve descriptor pool overflow handling on batch reset") Closes: #7485 (closed)