Fix IBC amount handling #4898

Job	Run time
build-wasm (ubuntu-20.04, v2, 1.11.0)	4m 23s
namada-release (ubuntu-20.04, 1.11.0, ABCI Release build, namada-e2e-release, v2)	11m 16s
namada-e2e (ubuntu-20.04, nightly-2023-06-01, 1.7.0, 0.37.2, 1.6.0-namada-beta1, e2e, 0, namada, ...	17m 48s
namada-e2e (ubuntu-20.04, nightly-2023-06-01, 1.7.0, 0.37.2, 1.6.0-namada-beta1, e2e, 1, namada, ...	19m 21s
namada-e2e (ubuntu-20.04, nightly-2023-06-01, 1.7.0, 0.37.2, 1.6.0-namada-beta1, e2e, 2, namada, ...	19m 27s
test-wasm (ubuntu-20.04, v2, nightly-2023-06-01, 1.11.0)	7m 0s
unit-and-integration-tests (ubuntu-20.04, nightly-2023-06-01, 1.11.0, ABCI, namada, v2, tendermin...	16m 57s
update-wasm	0s
	1h 36m 12s

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