docs: remove section on updating cart's customer #33543

Job	Run time
setup	1m 54s
Shard (0) Unit Tests	8m 40s
integration-tests-packages	12m 43s
Shard (1) Unit Tests	5m 8s
Shard (0) HTTP Integration Tests	11m 37s
Shard (0) Module Integration Tests	10m 44s
Shard (1) HTTP Integration Tests	9m 0s
Shard (1) Module Integration Tests	9m 35s
unit-tests	1s
integration-tests-modules	1s
integration-tests-http	1s
	1h 9m 24s

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