fix(apps/callbacks): use raw app ack bytes in the v2 async receive callback - #9079

Description

In the IBC v2 callbacks middleware the destination callback invoked from OnRecvPacket receives a RecvAcknowledgement, so ack.Acknowledgement() returns the raw application acknowledgement bytes. The asynchronous WriteAcknowledgement path wrapped the same bytes in a channeltypesv2.Acknowledgement, whose Acknowledgement() returns the protobuf encoding of the wrapper. A contract therefore observed different acknowledgement bytes for the same packet depending on whether the application acknowledged synchronously or asynchronously.

This PR uses RecvAcknowledgement in the async path too and adds TestWriteAcknowledgementCallbackAckMatchesSyncPath, which records the bytes delivered to the contract keeper on both paths and requires them to be equal (on main it fails with {"result":"AQ=="} vs 0a 11 {"result":"AQ=="}).

closes: #9074

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