fix(bqjdbc): update shading to be more targeted #20854

Job	Run time
changes	1m 9s
gapic-libraries-bom	20m 41s
lint	3m 36s
enforcer	21m 13s
generation-config-check	1m 47s
bulk-filter	1m 6s
windows	2m 24s
units (8)	56s
units (17)	32s
units (11)	38s
units (25)	32s
units (21)	31s
split-clirr (java-bigquery)	4m 16s
split-dependencies (java-bigquery)	5m 4s
split-units (java-bigquery, 8)	5m 22s
split-units (java-bigquery, 25)	5m 59s
split-units (java-bigquery, 17)	5m 25s
split-units (java-bigquery, 11)	6m 19s
split-units (java-bigquery, 21)	5m 46s
conditional-required-check	3s
	1h 33m 19s

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