CI: add smoke test for command validation

[tuhaihe]

Add smoke test to verify all cloudberry-backup commands (gpbackup, gprestore, gpbackup_helper, gpbackup_s3_plugin, gpbackman) can be built, installed to GPHOME, and executed with --version and --help flags.

This provides fast feedback on basic functionality before running more expensive integration tests.

closes: #ISSUE_Number

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[leborchuk]

Compared it with the generated package contents:

apache-cloudberry-backup-incubating-2.1.0-linux-amd64/bin/gpbackman
apache-cloudberry-backup-incubating-2.1.0-linux-amd64/bin/gpbackup_helper
apache-cloudberry-backup-incubating-2.1.0-linux-amd64/bin/gpbackup_s3_plugin
apache-cloudberry-backup-incubating-2.1.0-linux-amd64/bin/gprestore
apache-cloudberry-backup-incubating-2.1.0-linux-amd64/bin/gpbackup

All binaries in a place. Also manually checked if version and help works. Everything is Ok, print --version is good for smoke test