fix: Move the logic of getting systemProductName from static block to static method #7097

Job	Run time
build (11)	13m 3s
build(21) except self-service clients	11m 24s
build (17)	12m 39s
build(8) for gapic-generator-java	9m 46s
build(8) except for gapic-generator-java	4m 27s
lint	28s
compatibility	1m 29s
gapic-generator-java-bom	1m 49s
showcase (11)	3m 48s
showcase-native	8m 54s
showcase-clirr	3m 21s
showcase (17)	4m 27s
unmanaged_dependency_check	4m 39s
dependency_analyzer_unit_test	13s
	1h 20m 27s

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