chore(samples): Refactor gapic samples to not have try with resources #951

Job	Run time
filter	1m 0s
downstream-compatibility-spring-generator	11m 36s
downstream-compatibility (java-firestore)	3m 57s
downstream-compatibility (java-pubsub)	3m 49s
downstream-compatibility (java-bigtable)	3m 14s
downstream-compatibility (java-pubsublite)	4m 13s
	27m 49s

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