[test]Add more partitions in br test #429

Job	Run time
test-backup-restore-cross-version (docker-compose, standalone, standalone)	4m 2s
test-backup-restore-api (docker-compose, standalone)	37m 15s
test-backup-restore-api (docker-compose, cluster)	38m 25s
test-backup-restore-api (helm, standalone)	41m 18s
test-backup-restore-with-custom-config (helm, standalone, milvus-backup)	6m 10s
test-backup-restore-with-custom-config (helm, standalone, milvus-bucket)	5m 30s
test-backup-restore-with-custom-config (helm, standalone, file, milvus-backup)	5m 26s
test-backup-restore-with-custom-config (helm, standalone, file, milvus-bucket)	6m 5s
test-backup-restore-cli (docker-compose, standalone, standalone)	4m 22s
test-backup-restore-cli (docker-compose, standalone, cluster)	4m 21s
test-backup-restore-cli (docker-compose, cluster, standalone)	4m 25s
test-backup-restore-cli (docker-compose, cluster, cluster)	4m 19s
	2h 41m 38s

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