feat: add full RetrySettings sample code to Settings classes #7554

Job	Run time
build(8) for gapic-generator-java	11m 29s
compatibility	1m 38s
build(21) except self-service clients	13m 38s
build (11)	14m 56s
build (17)	15m 37s
gapic-generator-java-bom	2m 2s
lint	21s
showcase (11)	4m 0s
showcase (17)	4m 6s
showcase-native	8m 10s
unmanaged_dependency_check	4m 30s
showcase (21)	3m 59s
showcase-clirr	3m 4s
build(8) except for gapic-generator-java	4m 31s
dependency_analyzer_unit_test	21s
	1h 32m 22s

Provide feedback