CORTX-33534: Improve logs-cortx-cloud.sh error handling.

[walterlopatka]

Description

Improved error handling in logs-cotrx-cloud.sh:

• On kubectl failures, exit function early (and avoid additional, unhelpful error messages)
• Avoid "kubectl cp" with leading slash (/) on target, which causes an annoying "tar" error.

Type of change

• [x] Bug fix (non-breaking change that fixes an issue)
• [ ] New feature (non-breaking change that adds new functionality)
• [ ] Breaking change (bug fix or new feature that breaks existing functionality)
• [ ] Third-party dependency update
• [ ] Documentation additions or improvements
• [ ] Code quality improvements to existing code or test additions/updates

Applicable issues

• This change fixes an issue: CORTX-33534

CORTX image version requirements

N/A

How was this tested?

Local test:

• Verify no regression
• Test with pods evacuated from one node to see response to kubectl errors

Checklist

• [x] The change is tested and works locally.
• [ ] New or changed settings in the solution YAML are documented clearly in the README.md file.
• [x] All commits are signed off and are in agreement with the CORTX Community DCO and CLA policy.

If this change requires newer CORTX or third party image versions:

• [ ] The image fields in solution.example.yaml have been updated to use the required versions.
• [ ] The appVersion field of the Helm chart has been updated to use the new CORTX version.

If this change addresses a CORTX Jira issue:

• [x] The title of the PR starts with the issue ID (e.g. CORTX-XXXXX:)