backupccl: deflake TestDataDriven_external_connections_privileges

[stevendanna]

This test already tests the permissions end-to-end by asserting that the user can or cannot complete the expected actions. No need to print the system database as well.

Fixes #123379 Release note: None

[cockroach-teamcity]

This change is 

[stevendanna]

bors r=msbutler

[craig[bot]]

Build failed:

• check_generated_code

[stevendanna]

bors retry

[craig[bot]]

Build succeeded:

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• linux_amd64_fips_build
• local_roachtest
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