HDDS-7373. Add Robot acceptance tests for ozone --validate classpath

[arunsarin85]

What changes were proposed in this pull request?

This change adds Robot Framework acceptance tests for the Ozone CLI --validate behavior introduced under HDDS-7363, so installs are checked automatically for:

1. ozone --validate classpath <ARTIFACTNAME> - all jars listed in the artifact’s .classpath file exist
2. Failure cases - missing classpath descriptor, missing jar
3. Invalid usage - --validate with a subcommand that does not participate in validation (expects usage text)
4. continue + daemon - after validation reports missing jars, execution continues when --validate continue is used with --daemon status scm

Please describe your PR in detail:

Tests are added under hadoop-ozone/dist/src/main/smoketest/cli/classpath.robot next to the existing ozone classpath tests.
Cases added:

• Success: ozone --validate classpath ozone-insight → validation success messages, exit 0.
• Missing file: unknown artifact → exit 1, missing descriptor error.
• Missing jar: modified copy + ozone --validate classpath ozone-insight → exit 1, per-jar error and failure message.
• Usage: ozone --validate version → exit 1, usage contains “Usage I: ozone --validate classpath”.
• Continue: modified copy + ozone --validate continue --daemon status scm → “Continuing command execution” in output.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-7373

(Parent / related implementation: https://issues.apache.org/jira/browse/HDDS-7363)

How was this patch tested?

1. Local acceptance (Docker): Built smoketest into the dist layout, brought up the unsecure compose cluster (compose/ozone), ran execute_robot_test scm cli/classpath.robot, and confirmed 8/8 Robot tests PASS (output XML: all tests green; new cases show expected validation messages and exit codes).

[robot-001.xml](https://github.com/user-attachments/files/26490351/robot-001.xml)