Fix resource leak in gateway when using Pulsar #2666

Job	Run time
CLI End to End tests	11m 7s
End to End tests (Python, python)	20m 2s
End to End tests (Other, other)	18m 28s
Unit tests (Runtime)	6m 49s
Unit tests (Runtime IT)	18m 25s
Unit tests (Deployer)	7m 43s
Unit tests (Api Gateway)	8m 31s
Unit tests (Control plane)	4m 22s
Unit tests (Other)	11m 42s
Unit tests (Style)	4m 9s
	1h 51m 18s

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