build: update monorepo-migration scripts #17250

Job	Run time
owlbot-py	1m 24s
group_id_check_for_maps_libraries	8m 7s
gapic-bom	1m 41s
generate-readme	1m 6s
package_name_check	1m 13s
root-pom	1m 57s
gitignore_correctness	1m 1s
owlbot-yaml	1m 1s
	17m 30s

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