fix(bqjdbc): update shading to be more targeted #19187

Job	Run time
generate-readme	1m 14s
gitignore_correctness	1m 6s
package_name_check	1m 5s
owlbot-yaml	1m 7s
group_id_check_for_maps_libraries	9m 19s
gapic-bom	1m 38s
owlbot-py	1m 14s
root-pom	1m 44s
	18m 27s

Provide feedback