fix(IBC): remove denom registration fees. validate OnRecvPacket initially

[mtsitrin]

Description

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Closes #XXX

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• Import/Export Genesis
• Registered Invariants
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• No serialized ID at the end of store keys
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[danwt]

Looks OK but not sure about this if ack==nil

[danwt]

I dont' get this
It should never be nil, because we know the transfer stack

also

// Only save the packet if the underlying app's callback succeeds.

not really accurate due to this

[omritoptix]

basically we have the pfm which can return nil in case this metadata is provided (which we currently don't support)

[mtsitrin]

It should never be nil, because we know the transfer stack

right, that's what it's validates