Do not discard auth command if no args

[markusheiden]

Description

The authentication command (user.exec.args: command) from the .kube/config won't be discarded if no arguments are specified (user.exec.args: null).

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change
• Chore (non-breaking change which doesn't affect codebase;
  test, version modification, documentation, etc.)

Checklist

• Code contributed by me aligns with current project license: Apache 2.0
• I Added CHANGELOG entry regarding this change
• I have implemented unit tests to cover my changes
• I have added/updated the javadocs and other documentation accordingly
• No new bugs, code smells, etc. in SonarCloud report
• I tested my code in Kubernetes
• I tested my code in OpenShift

Fixes #3733
Backport for the 5.12 branch: #4122

[markusheiden]

Due to problems in the master branch that are not related to this PR I was not able to test my code at all. How to progress?

[manusa]

Due to problems in the master branch that are not related to this PR I was not able to test my code at all. How to progress?

Could you please elaborate on the problems?

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

85.7% Coverage
0.0% Duplication

[markusheiden]

I tried again and it worked. Maybe I used the wrong JDK before.

[manusa]

This issue was also tackled on #4381, I'll merge some of the changes in this PR into the other one and close it.