bug: fix ibc transfer from canto to external chain

[dudong2]

Description

• Fixes an issue that caused a nil pointer error when doing an ibc transfer to an external chain because the ibc's transfer keeper had an ics4 wrapper of nil when it was created.

how to test

• check that ibc transfer from canto to external chain is performed well without panic

Closes: #XXXX

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[zsystm]

LGTM